Content MONOGRAPH OF MACROSTOMIDA AND HAPLOPHARYNGIDA (PLATHELMINTHES: RHABDITOPHORA) Anno Faubel

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1 MONOGRAPH OF MACROSTOMIDA AND HAPLOPHARYNGIDA (PLATHELMINTHES: RHABDITOPHORA) by Anno Faubel Content Introduction 3 Morphological Account 5 Strategy on Taxonomy 5 Terminology 5 Morphology: 6 Size, Shape, Colour 6 Epidermis and Cilia 6 Rhabdites, Rhammites 7 Cleptocnides 8 Body-wall Muscles 8 Sensory Organs 9 Duo-gland Adhesive Organ 12 Cephalic Glands 12 Spicular Skeletons 12

2 Nervous System 13 Excretory System 13 Mouth, Pharynx, Intestine 16 Prostatoid Organs 18 Reproductive System: 19 Testis 20 Ovary 22 Male Reproductive System 23 Female Reproductive System 27 Embrypology, Postembryology 28 Cytology 30 Self-fertilisation, Asexual Reproduction 31 Regeneration 33 Karyology 34 Molecular Analysis 35 Phylogeny 37 Systematic Account 39 Order Macrostomida Meixner, Family Microstomidae 40 Family Macrostomidae 65 Family Myozonidae 176 Family Dolichomacrostomidae Rieger, Subfamily Dolichomacrostominae Rieger, Subfamily Karlingiinae Rieger, Subfamily Bathymacrostominae Faubel, Order Haplopharyngida Karling, Family Haplopharyngidae Karling, Ecological Account 222 Sampling, Culture Experiments, Histological Techniques 222 Distribution, Abundance, Migration 223 Biomass 234 Reproduction and Life Cycles 235 Tolerance Experiments 239 Geographic Distribution 241 References 241 Appendix 265 Abbreviations of deposition of locations of types 265 Abbreviations of zoogeographic regions (Wallace) 265 Abbreviations in text, figures, tables, and plates 266 Delimitations of the Seas (maps) 269 Russian oblasts (map) 273 2

3 Introduction All but two centuries ago, in 1831 Ehrenberg established the Classis Turbellaria subdivided into the Ordo I Dendrocoela and Ordo II Rhabdocoela and furthermore both these orders in numerous families and genera. Since that time several authors, Diesing 1850, 1862, Schultze 1851, Schmarda 1859, Uljanin 1870, Hallez 1879, developed continuing systems based on new findings and new combination of characters. Taking into consideration all the character combinations of these systems which were partly greatly divergent, von Graff (1882) created a new system drawn on the following basal characters: form of gut and pharynx, asexual and sexual reproduction and type of female germ cells, i.e. development of ovaries or germaria and vitellaria. The system of the Ordo Turbellaria was subdivided, as it was done by Ehrenberg, into the Subordo I Rhabdocoelida and Subordo II Dendrocoelida. The Subordo Rhabdocoelida was farther subdivided into the Tribus Acoela, Rhabdocoela and Alloiocoela (later Alloeocoela) (Fig. 1). The system established by von Graff (1882), represented an important jump ahead and remained valid over a long period in its main features. Decades later, Karling (1940) and Westblad (1948) and, finally, Ax (1961) established a modified system of the Turbellaria subdivided in Archoophora (species with entolecithal eggs) and Neoophora (species with ectolecithal eggs) and raised the Macrostomida, Acoela and Catenulida to order level. Ax (1956a) gave both the taxa Archoophora and Neoophora the status Stadiengruppe because phylogenetically both taxa do not represent natural groups. Based on several primitive characters, i.e. cellular epithelia, pharynx simplex, ciliated gut, paired protonephridia and simple genital system, Ax (1961) allocated the Macrostomida a basic position in the Stadiengruppe Archoophora. Today, the Turbellaria, a paraphyletic group, were subdivided into the clades Acoelomorpha, Catenulida and Rhabditophora, each a monophyletic group. In this system the Macrostomida represent the most basal group within the Rhabditophora. Based on comments of Schultze (1851) and Claparède (1863) and on the description of the species Macrostomum hystrix Oersted and the new species Macrostomum viride van Beneden, Ed. van Beneden (1870) established the new family Macrostomidae including the genera Macrostomum van Beneden, Omalostomum van Beneden and Mecynostomum van Beneden within the tribus Rhabdocoela Ehrenberg. The family Macrostomidae was characterised by von Graff (1882) as follows, two genital openings, the female pore anterior to the male pore, with ovaries but without accessory female organs ( Hülfsapparate von Graff 1882) and with pharynx simplex. Many years later, 1948, the genus Mecynostomum was transferred by Westblad to the taxon Acoela based on the redescription of Mecynostomum auritum (Schultze, 1851). The family name Microstomeae O. Schmidt, 1848, was emended by von Graff, 1882, to Microstomidae and characterised by the accomplishment of a vegetative and generative reproduction, presence of a single ovarium, absence of female accessory organs and possession of a pharynx simplex. To this family, the genera Microstomum Schmidt,1848, Stenostomum Schmidt, 1848, and Alaurina Busch, 1851, were affiliated. In 1905, the genus Stenostomum was excluded by von Graff from the Microstomidae and transferred to the new family Catenulidae von Graff. The taxon Macrostomida, as characterised by von Graff, remained valid up to date although constantly new findings and descriptions of a great number of species occurred. In 1971b, Rieger expanded the order with the establishment of the new family Dolichomacrostomidae. The family Haplopharyngidae, once established by Karling (1965), were ranked by him to order level (1974a). The intention of this monograph is to present a complete review of the Macrostomida and Haplopharyngida (Plathelminthes) on taxonomic, systematic, ultrastructural, chemotaxonomic, ecological and phylogenetic treatments. Informations will be given to molecular and physiological aspects. It is not the intention to create a new system based on recent 3

4 phylogenetic considerations or on molecular and genetic implications because it is evident that morphological and molecular data in many respects lead to contradictory results. However, new taxonomic considerations, emendations and establishments of new taxa within the system prepared, are based on cladistic approaches which will follow the phylogenetic Fig. 1. Phylum of the Turbellaria after von Graff, The first tree-like system established at all, taking into consideration cladistic relationships. principles after Hennig (1966). On principle, this monograph should be predominantly a help for taxonomists and ecologists to enhance the determination of free-living Macrostomida and 4

5 Haplopharyngida on species level and provide informations to all who will be busy with Macrostomida. With the exception of the publication made by Ax (2008), recent informations dating from 2006 to now could not accounted for completely. For all species synonyms, types, type localities, deposition in musea if the deposition was recorded, habitats, geographic distribution, morphological notes abridged, and ecology if something is known, will be presented. The geographic zoogeography of marine species is ordered after sea area delimitations (see Figs 94-98). The zoogeography of species inhabiting freshwater and terrestrial biotopes is ordered after Wallace' Geographical Regions (cf. p. 265). The zoogeography of European Russia is ordered after greater compartments of Russian oblasts (see Fig. 99). Morphological Account Comprehensive papers on the biology of Turbellaria containing greater parts of the Macrostomida, are as follows: anatomy and morphology (Ax 2008, Ferguson 1939a-c, 1940a c, Luther 1960, Papi 1951b, 1953, Rieger et. al. 1991), ultrastructure of integuments (Tyler 1976, 1984), anatomy and phylogeny (Ehlers 1985, Hyman 1951, Rieger et al. 1991). Strategy on Taxonomy Characters valid on species level, are general features of the morphology and anatomy of the body regarding outline, colour, eyes, epithelia, epidermis (rhabdites, rhammites, pigments, crystalline bodies etc.), parenchyma, genital pores (common or separate), false and true seminal vesicles, lining of ducts (i.e. presence of glands, muscle fibres, hard structures etc.), prostatoid organs, and structure of pharynx, gut and copulatory apparatuses. Characters valid on genus level are number of testes and ovaries (single or bilateral), presence of cirrus or penial stylet, antrum masculinum, seminal vesicle, prostatic vesicle, prostatic vesicle reduced or being not, and intestinal communication with the genital apparatus via a genito-intestinal duct. Terminology The terminology of terms applied to Macrostomida and Haplopharyngida presented in this monograph, is adopted to earlier papers of reviewal intention (Ferguson 1940b, 1954, Westblad 1953, Marcus 1949, Papi 1953, Luther 1962, Rieger 1968, 1971b, c) but some of the terms have to be supplied with modifications where it was considered necessarily, others must be defined newly. Positions of organs in the body, right or left side, are given from dorsal view in direction of movement and not from frontal view. Morphology Size, Shape, and Colour Most macrostomids (Plate IV: A-O) are mm in length, of longish outline, and dorso-ventrally flattened. Longish, thread-like forms could reach length of more than 4mm. 5

6 Maximum length of 5.0mm (exceptionally 8.0mm), 4.0mm and 6.0mm will be reached by members of the Microstomidae (Microstomum lineare) when asexually chaining, Dolichomacrostomidae (Myozonaria bistylifera), and Haplopharyngida (Haplopharynx rostratus), respectively. Members of the family Macrostomidae, especially, of the genus Macrostomum often exhibit a typical macrostomid shape, i.e. the posterior tail region being more or less deeply waisted at level of the sex apparatus or behind it, is typically spatulated, terminally truncated or bluntly pointed and provided with a rim of adhesive glands for sticking to surfaces. The anterior end of the body is frontally truncated or bluntly rounded, sometimes head-shaped. The middle portion of the body is broadest. Microstomidae are thread-like cylindrical and characterised by a head-shaped fore-end which is posteriorly constricted by an annular ciliated groove anterior to brain and pharynx simplex. Body ends are more or less rounded. Species of Dolichomacrostomidae and Haplopharyngidae are often thread-like cylindrical with rounded body ends. Some species of the genus Paromalostomum are characteristically provided with knob-shaped darker head and truncated body end. In t.l. the body of most of the species, especially interstitial forms, seems to be dirty grey (often longer individuals) or colourless but intestine taking on colouration when food ingested (diatoms, foraminifers, and/or dinoflagellids). Planctonic or epibenthic species or species thriving as aufwuchs on algae, could be coloured green or yellowish green through algal symbionts distributed in the tissues. In i.l. most forms looks whitish unless they are intensively pigmented or are carrying algal symbionts. Epidermis and Cilia The whole body is walled with a uni-layered, multi-ciliary, cellular epidermis (Fig. 2A) the nuclei of which are lying intraepithelial or are adenal (Tyler 1984). Microvilli, finger-like projections, cover the surface of all ciliated cells. Apically, the epithelial lining contains epitheliosomes (ultrarhabdites called by Bedini & Papi 1974, Tyler 1984), electron-dense, small granules, often responsible for colour. Pigment, however, must not be restricted to epitheliosomes but can be scattered throughout the lining. Just under the epitheliosome layer a cell web (Bedini & Papi 1974) called terminal web (Tyler 1984, Rieger et al. 1991), is developed, which is oriented parallel to the epithelial surface with probably skeletal function (Ehlers & Sopott-Ehlers 1997). It consists of sheet-like arrangement of microfilaments. All cells are held together by zonulae adhaerentes and septate junctions, forming belts around the apical end of cells, however, they are developed to different degrees in different species. Haplopharynx sp. and Microstomum sp. have well developed zonulae adhaerentes; septate junctions could be relatively inconspicuous as developed in Bradynectes sp. (Tyler 1984). The epithelial lining is interspersed with three different types of glands: cyanophilous mucus glands, adhesive glands and rhabdite glands (Reisinger & Kelbetz 1964). All rhabdite glands contain rod-shaped secretions which are embedded adenal in the peripheral parenchyma. Exceptions are reported. After Smith et all (1982), the rhabdite glands lie either in the epithelial layer or adenal in parenchyma in Psammomacrostomum sp. Rhabdites are dispersed over the body surface either individually or in groups containing 2 up to 10 rods. The concentration in the number of rhabdites often increases to the body-ends. Adhesive glands intensively developed at the rim or over the spatulate posterior end of the body, serve for sticking to substrates. Sticking to substrates prevents drifting away. A basement membrane, an extracellular matrix (ECM), is present and consists of granular fibrillar material (Ehlers 1985). After Rieger et al. (1991) the extracellular matrix is not as sharply set off as basement membrane, but appears as an extension of a general intercellular matrix that lies between muscle and other subepidermal cells. The outer surface of the epidermis is totally covered with cilia which are regularly arranged in rows. Cilia are composed of the ciliary shaft with an axoneme pattern of

7 microtubules, a basal body and two rootlets oriented at approximately right angles to one another or the perpendicular one extends somewhat caudally (Bedini & Papi 1974). The ciliogenesis was studied by Tyler (1981) on Macrostomum hystricinum marinum. In 39-41h embryos, epidermal blastomeres reveal clusters of presumptive basal bodies (centrioles) as a result of generation of new centrioles besides fully formed ones. These centrioles (presumptive basal bodies) are morphologically distinguishable from centrioles of the mitotic apparatus. In these epidermal blastomeres clusters of centrioles (presumptive basal bodies), procentrioles (centrioles with raspherry-like profile) and, more rarely, mitotic centrioles are assembled. The presumptive basal bodies migrate to the apical plasma membrane through the terminal web, proceeding in production of ciliary axonemes by an age of hours. Rhabdites, Rhammites As before v. Graff (1882) already suggested after the study of living Macrostomum hystricinum, Luther (1905) discerned 4 types of rhabdites within the Macrostomida: rodshaped rhabdites (1), rhammites (2) developed in glands (rhammite glands) lateral of brain and pharynx (the necks of the glands converge just caudal of brain and pass through or ventral of it to the frontal end in rhammite tracks Stäbchenstrassen of German authors - (cf. Klauser et al. 1986, Klauser & Tyler 1987), single-edged, thread-like tapered rhabdites (3), and micro-rhabdites (4) arranged around rim of mouth. Investigations on Macrostomum species (Reisinger & Kelbetz 1964) demonstrated that within a species all these types of rhabdites coincide exactly in their ultrastructure. The organisation of a Macrostomum rhabdite Fig. 2. Ultrastructure of epidermis cell (A) and longitudinal section of Macrostomum rhabdite (B). B. Middle part of rhabdite in spacial construction by omitting the inner structures for demonstration the fibril pattern. Figures modified after Reisinger & Kelbetz 1964 and Bedini & Papi (Fig. 2B) is extremely complicate and consist of several layers of fibrils and a granulated inner mass. A polar body could be present in the distal part of that rhabdite subtype. In experiments of adding chemicals in very low concentration to slightly squashed individuals under a coverslip (i.e. solution of Lugol, 0.05% OsO 4, Champy), Reisinger and Kelbetz demonstrated the expulsion of rhabdites. The discharge started at the posterior end and corresponds a moisture expansion by solving the inner genuine structure. 7

8 Rhabditogen cells have been examined by Smith et al. (1982) in several species of Macrostomida: Psammomacrostomum sp., Microstomum sp., 3 Macrostomum spp., Paromalostomum sp., Myozona sp. and Paramyozonaria sp. The exception being Psammomacrostomum sp., the rhabditogen cells are located in the parenchyma beneath the body muscle wall. In Psammamacrostomum sp. the rhabditogen cells lie either in the epidermis or in the parenchyma. Mature rhabdites are discharged through neck-like extensions of the rhabditogen cell. The gland neck of Psammomacrostomum sp. is supported by microtubules (Smith et al. 1982). Based on EM studies to the ultrastructure of rhabdites, Smith et al. (1982, p ) proposed a definition of a rhabdite as follows: rod-shaped secretions, of varying lengths and approximately 1µm in diameter, which are acidophilic, refractile, and membrane-bounded, with one to several concentric striated lamellae constituting its cortex, and with a concentrically lamellated, granulated, or homogenous medulla; formation within a gland cell with the cortical organisation emerging first and with a microtubular sheath occurring external to the unit membrane; release to the exterior through neck(s) of the gland cells that protrude(s) either between epidermal cells or through epidermal cells. Within the Macrostomida, the Macrostomum subtype and the lamellated subtype is dominantly developed. The lamellate subtype consists of a variable number of concentric lamellae and the Macrostomum subtype has three electron-dense fibrillar cortical layers. The Macrostomum subtype, present within the genus Macrostomum, differ in the presence or absence of a polar body. Within the Macrostomida, generally, the lamellated type is developed. Cleptocnides Microstomidae integrate in their tissues, i.e. epidermis, parenchyma and intestine, true cleptocnides (nematocysts) (Fig. 46, p. 46). The nematocysts are allochthonous and originate from cnidarian prey. Nematoblasts responsible for the transport of the cnids into the tissues, have not been found but there is evidence of transport by indigenous parenchmal cells (Karling 1966). The subepidermal cnid-containing cysts are of the same origin as the basement membrane produced by adjacent cells outside the cyst, most distinctly in Microstomum lineare - and often provided with a muscular stratum derived from the subepidermal musculature. The function of the cleptocnids is evidently a useful protection against predators (Karling 1966). Body-wall Muscle The general pattern of the body-wall muscle is a trefold layered grid of fibres, i.e. outer circular muscle fibres, innermost longitudinal muscle fibres and in between diagonally oriented muscle fibres. The diagonal fibres crossing each other, angle clockwise and counterclockwise around the body. In smaller organisms the diagonal muscle layer may be very weak or may be absent. After Rieger et al. (1991), re-investigation of several species of Microstomum and Macrostomum revealed a three layered body-wall musculature. Restudy of Paromalostomum fusculum offered that a diagonal sublayer is absent. Based on these results, Rieger et al. (1991) believe that the presence of a diagonal sublayer may be characteristic of the genera Microstomum and Macrostomum. Diagonal muscles are absent in the genus Paromalostomum or even in all species of the Dolichomacrostomidae. 8

9 Sensory Organs Sensory organs of the Macrostomida are caudal sensory organs, ciliated pits, and photoreceptors: pigmented eye-spots and eyes of the rhabdomeric ocelli type. Ciliated Pits. The ciliated pits of Microstomum lineare were investigated on its ultrastructure by Palmberg (1995). These pits are bottle-shaped grooves opened to the lateral margin at level of the brain. They consists of two type of cells. The one cell type lying postero-lateral, is characterised by several cilia with prominent rootlets, apical mitochondria and a Golgi-complex with amorphous vacuoles of different sizes. The other cell type is provided with numerous microvilli besides cilia, abundant microtubules and electron-dense granules apically. A few multiciliary receptors lie between these cells. The pits are innervated by fibres from lateral nerve cords and from brain. Immunoreactivity to neuropeptides, FMFR/Ramide, NPF and substance P were observed in these fibres. The function of the ciliary pits are argued by Palmberg (1995) to be chemoreceptive. The close connection to the protonephridium indicated the possibility that they are involved in osmoregulation (Palmberg 1995). Photoreceptors. Pigmented eye-spots of Microstomum lineare studied by Palmberg et al. (1980), consist of two ciliary photoreceptor cells surrounded by pigment cells and additional sensory cells. The photoreceptor cell is composed of a distal intracellular cavity lined with interwoven cilia. The other sensory cells are either with long cilia which are predominating, or with balloon-like cilia. Fig. 3. Photoreceptors of Macrostomida. A. Rhabdomeric ocelli type of Macrostomum spirale (after Kunert & Ehlers 1987). B. Membrane amplification type of Microstomum lineare; arrowhead - ciliary lamellate body; long arrow - balloon-like cilia; short arrow long cilia (after Palmberg et al. 1988). Abbreviations of the receptor cells (rc): drc, mrc, rrc, and vrc = dorsal, median, ring-shaped, and ventral receptor cells, respectively. The photoreceptors of Macrostomida belong to the rhabdomeric ocelli type (Fig. 3A, 4A). Ciliary cell membrane differentiations were accounted for Macrostomum spirale as photoreceptor (Palmberg et al. 1980, Kunert & Ehlers 1987), in Cylindromacrostomum notandum, Paramyozonaria simplex, Macrostomum hystricinum marinum, Myozona purpurea, Bradynectes sterreri and Nynaeshamnia turbanelloides (Sopott-Ehlers et al. 2001). 9

10 The rhabdomeric photoreceptor is composed of pigment vesicles which encloses cupshaped, fingered projections, i.e. microvilli, of photoreceptive cells. The number of pigmentcup ocelli increases to four pairs within the Macrostomida; Cylindromacrostomum notandum, Paramyozonaria simplex, Macrostomum hystricinum marinum possess two rhabdomeric intracerebral photoreceptors each consisting of two pigmented cup cells and three (C. notandum, P. simplex) or two (M. hystricinum marinum) sensory cells (Sopott-Ehlers et al. 2001). Only 1 3 receptor cells were accounted for Polycladida and Neoophora (the exception being Dugesiidae, Tricladida). After Xylander et al. (1997), the increase in number of receptor cells (to four) is restricted to only few species of Macrostomum or even to M. spirale. The receptor cells are either in close contact to the brain or are embedded in it directly. The photoreceptive membrane amplification type (Palmberg et al. 1988) accounted for Microstomum lineare, consists of four different cell types: ciliary lamellate body, pigment cell, sensory cell with long cilia, and sensory cell with ballon-like cilia (Fig. 3B). Orii et al. (1998) used antiserum produced from cloned opsin cdna from the triclad Dugesia japonica Ichikawa & Kawakatsu, 1964, against the C-terminus of opsin to test immunohistochemically the presence of opsin in the photoreceptive organs of several turbellarian species. The antiserum produced positive reactions in the eyes of other triclad species and the polyclad Notocomplana koreana (Kato, 1937). No activity was observed in Macrostomum tuba as well as in Acoela (Praesagittifera naikaiensis (Yamasu, 1982) and Catenulida (Stenostomum sp.). Orii et al. (1995) estimated that the eyes of Macrostomum tuba, Acoela and Catenulida are not typically rhabdomeric as those of triclads and polyclads. Sensory cilia receptors. Sensory cilia receptors were reported for a wide range of Plathelminthes. Results on Macrostomida were reported by Ehlers (1977, 1985). The collar receptors of Microstomum spiculifer, Paromalostomum fusculum and Myozona purpurea are monociliary. The receptors of Haplopharynx rostratus have developed three cilia. Klauser & I have to desist from reproduction of Fig. 1, Xylander et al. 1997, in this context because Elsevier (Oxford, UK) did not grant permission to use Fig.1 without charge. Fig. 4. Diagrammatic reconstruction of eight (A-H) different receptors found in Macrostomum tuba. A. rhabdomeric receptor, B. Collar receptors, C. eight-cilia receptor, D. four-cilia receptor, E. monociliary receptor, F. gland-like receptor, G. bulbous-cilia receptor, and H. branching receptor (after Xylander et al. 1997). Tyler (1987) reported on three types of monociliary sensory cells, types I and II and balloonlike ciliary sensory receptors. The latter type was detected in Microstomum sp., Paromalostomum coronum, Myomacrostomum bichaeta and Myozona sp. (Klauser & Tyler 1987). Recent ultrastructural investigations (Xylander et al. 1997) on sensory cilia receptors (Fig. *4B-H) of Macrostomum tuba (M. bulbostylum is a synonym of M. tuba) revealed the highest number and diversity of receptors along the anterior margin where the authors estimated at least 200 individual receptors. The total number of receptors of M. tuba were calculated to exceed 300 receptors whereas especially those of types B, C, and E (Fig. *4) are dominantly present. In mid-body, the lowest number of receptors were found, dominantly the collar types 10

11 and types C, D, and E with long cilia and rootlets. The posterior end is provided with receptors of the types B 1 and B 2, C, D, E, and G but in lower numbers than along the anterior margin. The most frequent type is B2 whereas types D and E are rather rarely present, usually in close proximity of the adhesive glands (Xylander et al. 1997). Caudal Sensory Organ Rieger (1971b, c) reported a sensory organ in the posterior ends of some dolichomacrostomid species (Fig. 5A). The organ resembles a protonephridial Fig. 5. Ultrastructure of caudal sensory organ (cso) and duo-gland adhesive organ (dgao). A- C. Caudal sensory organ (after Rieger & Tyler 1974). A. Caudal sensory organ of Myozonaria jenneri. B. Cluster of caudal sensory organ. C. Fine structure of bulb cell. D-F. Duo-gland adhesive organ (after Tyler 1976). D. Ultrastructure of dgao of Paromalostomum sp. Tyler, E. Ultrastructure of dgao of Myozona sp. Tyler, F. Ultrastructure of dgao of Haplopharynx sp. Tyler, system through solenocyte-like cells which open into a common canal. Based on the immobility of the cilium in the connecting cell (Fig. 5C) led Rieger to ascribe this organ a sensory function. Based on new ultrastructural studies (Rieger & Tyler 1974) the caudal sensory organ consists of several bulbous primary sensory cells arranged in one or two grape-like clusters (Fig. 5A-B). The clusters are located deep in the parenchyme at the proximal end of a central canal which connects each cluster with the exterior. The clusters are arranged paired or unpaired and each cluster opens to the exterior with an own separate central canal. Paired clusters are lying laterally. A single one lies in mid-line of the posterior body part. In each bulbous cell of the cluster, a non-motile cilium rises, extending to the central canal, and joins with the cilia of the other bulbous cells (Fig. 5B). The cilia protruding 11

12 through an external opening in the epidermis, form a long ciliary tuft. The bulbous cell has developed an extensive endoplasmatic reticulum and Golgi complex suggesting a sensory function. The axonemes of the non-motile cilia display a highly modified fine structure with singlet patterns from to depending on sections made more proximally or distally of the cilium. The cilium is anchored in the cup-like terminal capsule being invaginated into the bulb cell (Fig. 5C). The wall of the terminal capsule bears microvilli of nm length by 150nm width. An axon of every sensory cup-like cell originates next to the cup-like invagination. The entire organ is innervated by two large nerves from each of the main lateroventral nerve cords. Duo-Gland Adhesive Organ The duo-gland adhesive organ described by Tyler (1976), is consisting of the three cell types viscid gland, releasing gland and anchor cell (Fig. 5 D-F). The anchor cell is a modified epidermal cell through which the necks of both the glands penetrate. The anchor cell surrounds the protruding gland necks with an array of microvilli fence-like. The microvilli of the anchor cell are modified as well and distinguish from the other microvilli of the epidermis by the presence of dense fibrous cores. The gland cells produce secretion granules of different morphology. Mature granules of viscid glands are dense and granules of releasing glands are smaller and less dense. Viscid glands are able to stick to surfaces and releasing glands are responsible for setting free. Cephalic Glands In the descriptions of macrostomid species, no great importance had been attached to the cephalic glandular system. Cephalic glands were at first clearly described by Luther (1960) from Microstomum lineare and by Westblad (1953) from M. hamatum. After Luther (1960), the cephalic glands are comparable to the frontal organ of Acoela. Ultrastructural and histochemical comparison on the cephalic glands of Macrostomida and frontal organs of Acoela made by Klauser & Tyler (1987), revealed that the organs are not homologous but at least analogous, both probably serving to produce mucus for locomotion (Martin 1978) and feeding by means of gardening food items found by the acoelous species Convoluta sp. (Klauser 1986). Cephalic glands were also reported by Rieger (1971b) from Dolichomacrostomidae and by Klauser & Tyler (1987) from Microstomum sp. and Macrostomum hystricinum marinum. The cephalic glandular ducts open to the exterior at the frontal body end interwoven with the ducts of the rhammite tracks if present. The glands of which lie in immediate proximity of the ganglion in the Microstomidae or far posterior of the ganglion in Dolichomacrostomidae (Rieger 1971b). The glandular ducts of dolichomacrostomids are crossing the brain as do the rhammite glandular ducts. The glandular ducts of the Microstomidae never cross the brain. Spicular Skeletons Within the Macrostomida only Acanthomacrostomum spiculiferum and A. gerlachi are known to have a spicular endoskeleton localised in the parenchyma (Fig. 72; Plate XXII: K,L,O). Based on the depressed epithelium in these species, Rieger and Sterrer (1975) are convinced on the exact relationship of spicules and epithelium. The spicules are most probably composed of calcareous material. They could be solubilised in mineral acids and histological fixatives such as Bouin s. The spicules are of hard consistency and break easily in squashed preparation (Rieger & Sterrer 1975). Papi & Swedmark (1959) believed the 12

13 endoskeleton be a special adaptation for the intertstitial environment as mechanical protection and based on the increased specific body weight, an increased protection for washing out from the interstitial habitat. Rieger & Sterrer (1975) believed the spicules have a supportive locomotory or adhesive function. Fig. 6. Nervous system of Microstomum lineare (after Reuter 1981and Reuter et al. 1995) A.- D. Nervous system based on neuropetid F immunoreactivity pattern. A. Pattern in longitudinal nerve cords, main (nm), dorsal (nd), and ventral (nv) cords. End cells (ec) marking completed development in tail end and close to division zones. B. Pattern in stomatogastric nervous system. C. Synapse-like structures between nerve terminal and muscle; membrane indentation and extruded granule core (arrow) D. Synapse-like structures on nerve cell soma; cleft filled with dense material. Nervous System According to Beklemishev (1969, p. 87) the nervous system represents a high degree of centralisation of the neural apparatus. The whole ventral and dorsal surface of the body is devoid of ganglionic cells. The pattern of the nervous system with a brain and three to five cords connected by commissures, is regarded as the basic plan of Turbellaria, the orthogon (Bullock & Horridge 1965). The typical nervous system of the Macrostomida is composed of a brain, i.e. cerebral ganglia, two lateral longitudinal stems (main nerve cords), minor nerve cords, and one transverse commissure of the ventral nerve cords posterior of the pharynx. The stomatogastric system consists of a pharyngeal nerve ring, joined by a pair of connective ganglia to the brain, and an autonomous plexus around pharynx and intestine (Fig. 6A.-B) (Reuter & Gustafsson 1996, Reuter et al. 1998). The brain is crescentic-shaped and composed of two ganglia joined by a short commissure which is represented by a slight indentation between the ganglionic neural masses, i.e. the brain is bilobed. The cephalic neural masses consist of a central matrix of unmyelinated 13

14 fibrous tissue surrounded by cell bodies, which form the peripheral nervous system and the stomatogastric system. The peripheral nervous system comprises submuscular and subepidermal plexi, i.e. the latero-longitudinal nerve stems arising from brain and extending anteriorly and posteriorly. Anterior stems are smaller and more numerous than posterior stems; some of them being in connection with the eyespots and ciliary pits (Reuter et al. 1980, Reuter 1981, Rieger et al. 1991, Reuter 1994, Reuter et al. 1998). Release sites of neurochemical messengers between aminergic neurites, at least in Microstomum lineare, are conventional synapses and synapse-like structures which contain dense core vesicles at the release sites (Fig. 6C-D). Peptidergic release sites are synaptoids resembling conventional synapses (Reuter 1981). The organisation of the nervous system of Microstomum lineare (Fig. 6 A-B) was studied by Reuter et al (1984, 1986, 1995, 2001) and Wikgren et al. (1986), based on immunocytochemical methods, the use of antisera to neuropeptides and bioamine serotonin. The nervous system of Macrostomum hystricinum marinum was studied by Reiter & Wikgren (1991) using immunoreactivity to SALMF-amide and by Ladurner et al. (1997) to serotonin (5-HT). Latter authors studied additionally the immunoreactivity to serotonin in Archimacrostomum pusillum. These immunostaining analyses documented the presence of a typical orthogon with three pairs of nerve cords, a main lateral pair, a ventral pair, and a dorsal pair. The immunoreactivity to SALMF-amide analysed by Reiter & Wikgren (1991), revealed additional fine subepithelial and submuscular nerve nets next to the nerve cords. The labeling of distinct neurons proved the filamentous nature of the main lateral nerve cords and the pharyngeal nerve ring system. All these immunocytochemical studies resulted in the establishment of the peptidergic system as the main component of the nervous system, containing a greater variety of potential transmitter substances than the cholinergic and aminergic systems (Fairweather & Skuce 1995). The development of a new brain and pharyngeal plexus in Microstomum lineare was studied by Reuter & Palmberg (1989) using immunocytochemical methods as well. The development and differentiation of neuronal subsets starts always in connection to the parental nerve cords. 5-HT antigenicity in the postpharyngeal commissure indicates the onset of the development of a new zooid. This observation of immunoreactivity in fibres and later in cells supports the suggestion that trophic substances from nerve terminals can control the growth of adjacent neurons (Reuter & Palmberg 1989). The importance of the parental nerve cords for the development of a new brain in asexually produced zooids is also documented through experiments to the evidence of catecholamines in the nervous system of microturbellarians (Reuter & Erikson 1991). Reuter (1983) studied the lytic activity in aminergic neurons in developemtal stages of zooids of Microstomum lineare. Differences arisen between neurons of developing and mature zooids. Three categories of differences in ultrastructure, size and nucleoplasmic index, were visible: (1) small aminergic neurons occurring in developing zooids, (2) flocculent aminergic neurons characterised by a network of flocculent splittings in the cytoplasm and (3) vacuolated aminergic neurons with large membrane limited vacuoles occupying a large part of the perikaryon. Excretory System The common excretory system of Macrostomida is composed of bilateral protonephridia which display multiple branching on each side. Each branching tubule ends proximally with a flame bulb. A flame bulb looks like a cup consisting of a terminal multiciliary cell (Fig. 7). The cilia project into the cavity of the cell cup and beating of the cilia drains fluids from the body tissues. The protonephridial, mostly coiled stem canals reach from level anterior of brain to caudal end with usually two nephridiopores to the outside. The nephridiopores mostly open 14

15 in the region between pharynx and just anterior to testes. Protonephridia are not restricted only to freshwater macrostomids but are also developed in marine forms (Brüggemann 1986a, Kunert 1988). Fig. 7. Ultrastructure of protonephridia. A. Macrostomum spirale (after Kunert 1988). B.-E. Paromalostomum proceracauda (after Brüggemann 1986a). C.-E. cross sections of the terminal complex indicated in B. The ultrastructure of the flame cells of the marine species Macrostomum spirale and Paromalostomum proceracauda was studied by Kunert (1988) and Brüggemann (1986a), respectively. In marine forms the protonephridia are hardly to observe under light microscopical conditions. That was the reason for the earlier general acceptance that marine forms of Macrostomida do not have protonephridia. Between brain and caudal end of M. spirale, terminal cell complexes exist which are composed of one multiciliated terminal cell and two canal cells surounding a ciliary tuft (Fig. 7A). The lumen containing the ciliary tufts (bundle of appr cilia, each 9µm long), is encircled by a two-cell weir (Fig. 7B) which is set up by an array of inner and outer row of microvilli surrounded by a weak layer of an extracellular matrix. Based on high vacuolarisation, numerous coated pits and vesicles, lysosomes and electron-dense vesicles, the second canal cells probably possess secretory or re-absorptive functions. The difference of the terminal complexes of M. spirale and Paromalostomum proceracauda (Fig. 7B-E) is founded in the fact (Brüggemann 1986a) that P. proceracauda has a terminal complex with three multiciliated terminal cells with separate filtration apparatuses arranged in different levels, a filtration weir with only one individual row of microvilli, and with a common canal cell directly adjoining the distal terminal cell of the terminal complex. The nephridial capillary consists of at least two tube-shaped cells disposed behind each other. Branching is possible if more than one terminal complex are be grouped into larger units. The protonephridum, flame bulb cell and proximal canal cell, of the Microstomidae (Rohde 1991) is characterised by a weir formed entirely by the terminal cell and consists of a single row of longitudinal ribs between some thicker columns of the cell (Fig. 8A,B). Ribs 15

16 and thicker columns are connected by a weak layer of extracellular matrix (Fig. 8A). Microtubules are present in some columns. Internal leptotrichs arise from the terminal cell between its cilia and from its ribs and columns and from the proximal canal cell. The proximal canal cell is surrounded by the apical part of the terminal cell, connected to it by septate junction. Fig. 8. Protonephridium of Microstomum sp. (A, B) Canal cell of Microstomum (B) and Macrostomum (C) in cross section through weir (after Rohde 1991). Mouth, Pharynx simplex coronatus, Intestine The pharynx simplex is developed as invagination of the epidermis conserving the epithelial and muscular layers of the body wall or with reversed muscle layers. Macrostomida and Haplopharyngida have developed a special type of pharynx simplex, the pharynx simplex coronatus (Doe 1981), because of a characteristic encircling nerve ring, a post-oral nerve commissure, and the special modification of the epithelia of the transition zone (Fig. 9). The nerve ring include more than 30 axons and the nerve commissure at leat 12 axons. The fine structure of the macrostomid and haplopharyngid walls of the pharynx simplex studied by Doe (1981), demonstrates its high epithelial specialisation distinct from the epidermis, in particular, in the transition zone (Fig. 9). The mouth region is restricted to the anterior and posterior edges at the transition from the ventral epidermis to the pharyngeal tube. The transition from mouth to pharyngeal tube is called the transition zone. This zone consists of a ring of 1 5 tiers of depressed cells with change of orientation of the ciliary rootlets as a consequence of the inward movement of the cells (Doe 1981). The cells are smaller, i.e. less surface area, and deeper than epidermis cells. They could bear cilia or cilia are absent (Haplopharynx). The transition zone characteristically represents the site entered by sensory cells and two or more types of glands discharging their mucus. 16

17 Fig. 9. Fine structure of pharynx simplex coronatus (after Doe 1981). A.-C. Morphology of the pharynx of Macrostomum sp. Doe. D-F. Morphology of the pharynx of Haplopharynx quadristimulus Ax. G. Pharynx and gastrodermis of Psammomacrostomum equicaudum Ax (after Ax & Faubel 1974). A, E and G. Reconstructions of pharynx and gastrodermis after light microscopical sections. B, C, D and F. Reconstructions of pharynx and gastrodermis after electronmicrographs. The gastrodermis (Fig. 9G, *10) consists of four different cell types (Reuter & Palmberg 1987): phagocytic cells, granular club cells (Minotian cells or glands), neoblasts, and gastrodermal neurons. Ciliated intestinal cells lost phagocytosis of solid food particles deduced by Metschnikoff (1878) based on observations in Microstomum lineare. Phagocytic cells are provided with microvilli and cilia (rootlets do not occur) and anchored in the basal lamina. Characteristic are abundant vacuoles varying in size, content and position. Club cells distribute between the phagocytic cells and are also anchored in the basal lamina. Cilia are absent but microvilli are present. The apical part of the cells contain large dark granules (1.8-4µm in diameter) and surrounded by a membrane. AcPase activity could not be observed suggesting phagocytic activity. Neoblast cells take a position between the intestinal lining close to the basal lamina. Gastrodermal neurons scattered within the gastrodermal lining (Fig. *10). They are not anchored in the basal lamina and get in no contact with the gut lumen. 17

18 The Macrostomida are dominantly predators on individuals ranging from smaller to somewhat bigger size than the predator himself. The prey spectrum comprises nearly all invertebrates like nematodes, polycheates or crustaceans living in the habitat proper. Diatoms or other algal components represent less objects of food. Holliman & Mecham (1971) reported that Macrostomum gigas (synonym of M. tuba) feeds on cercariae of Schistosoma mansoni Sambon, The general manner of ingestion is swallowing whole organisms as the pharynx simplex implies. The digestive tract of the Macrostomida and Haplopharyngida is unbranched, sack-like without any diverticula. The digestive tract has a distinct gastrodermis often interspersed with Minotian cells (Fig. 9G) ( Minotiansche Körnerkolben Westblad 1948, Ax 1961) or granular clubs and phagocytes. These Minotian cells are dominantly occurring in the distal region of the intestine. Basally, the intestine is underlaid by an extracellular matrix and circular muscle fibres I have to desist from reproduction of Fig. 1, Reuter & Palmberg 1987, in this context because Interscience Wiley (UK) did not grant permission to use Fig. 1 without charge. Fig. 10. Cell types of gastrodermis of Microstomum lineare. Arrow points to synapse (after Reuter & Palmberg 1987). Prostatoid Organs Prostatoid organs frequently existing in acoelous species, are less present in members of the Macrostomida. They are only known from Antromacrostomum armatum and species of the genus Haplopharynx (Haplopharyngida). Prostatoid organs are evidently organs with repugnatorial function in ordinary of copulation or preying. They are composed of distal pointed, sclerotised sections and proximal conglomerations of glandular prostatic cells. Von Graff (1911, p ) defined two types of prostatoid organs: prostomis striata and prostomis catinosa. Prostomis striata was defined to be an organ composed of a distal, single, sclerotised, spicular part with an inner duct to which a proximal, glandular section belong. Organs of prostomis catinosa type exhibit as well a single, sclerotised, pointed, distal part with an inner duct to which a proximal, glandular section belong. However, the distal sclerotised part is catenarianly composed of several plate- or funnel-shaped elements bored by an inner tube. Beklemishev (1929, p.234) and Westblad (1945, p. 7-8) were not committed to the evaluation and assignment of prostomes striatae and catinosae to distinct species of the Acoela, made by von Graff (1911). Beklemishev (1929, p. 234), therefore, defined a third type, prostomis composita, having a distal portion composed of several sclerotised pointed elements. Each of these elements is tubular and joined with a proximal gland of the proximal portion. Mostly and with hindsight, it is very difficult to decide between the types prostomis striata and prostomis catinosa. Therefore, if the type was not clearly determined by the author, prostatoid organs having distal portions with a single inner tube, are called prostomis striata, and prostatoid organs having distal portions composed of several tubular spicules, are called prostomis composita. Reproductive System Generally, Turbellaria are hermaphroditic but a few exceptions are known from different taxa (Apelt 1969, Ehlers 1985). The reproductive system comprises the male and female 18

19 genital complex. The development of male or female condition may be protandrous or protogynous whereas the protandrous condition is dominant. The male complex matches Fig. 11. Male copulatory apparatuses. A. Microstomum spiculifer Faubel, B. Dunwichia arenosa Faubel, Blome & Cannon, C. Antromacrostomum armatum Faubel, D. Myozona purpurea Faubel. Figs after Faubel 1974, Faubel, Blome & Cannon testes (unilateral or bilateral), vas deferens or vasa deferentia if bilateral testes are present, false seminal vesicles, ejaculatory duct referred to the lumen of the copulatory apparatus, and gonopore. The copulatory apparatus of Macrostomidae (Figs 11B-D, 16) and Microstomidae (Fig. 11A) consists of proximal seminal vesicle, prostatic vesicle, distal stylet, cirrus or antrum masculinum, and male atrium if present (Fig. 11). To date, cirrus (Fig. 11B,D) and antrum masculinum (Fig. 11C) are only known within the Macrostomidae and Myozonidae. The male copulatory apparatus of the Dolichomacrostomidae is characterised by a more complex organ. The stylet is joined with a glandular stylet. Distinct paired or unpaired accessory glands are mostly present. The male apparatus of Haplopharyngidae (Haplopharyngida) consists of a circle of needles. The female reproductive system of Macrostomida (Fig. 20, p.27) and Haplopharyngida matches single or bilateral ovaries, oviduct or ductus spermaticus, seminal bursa (seminal receptacle), vagina, female atrium and gonopore. The apparatuses of Microstomidae and Haplopharyngida look somewhat more primitive; a distinct seminal bursa and oviduct are absent. The family Myozonidae is characterised by a communicatio genito-intestinalis. This connection of the female duct with the intestine is believed to be an abortive canal for alien sperm received during copulation. On the contrary, the female copulatory apparatus of the Dolichomacrostomidae turns out to be highly specialised, in particular, the seminal bursa. The basal configuration consists of an atrial bursa and characteristic bursa pieces; the bursa pieces are composed of mouth-piece, mid-piece and spermtube(-s); the mouth-piece is provided always with 2 small disk-like thickenings at its distal end (Plate XXI). A special description is given for each species in the systematic account. 19

20 The copulatory apparatus is localised in the hind part of the body while the gonads are distributed anteriorly (Plate IV). The female copulatory organ is lying in front of the male one. The exception being, the male copulatory apparatus of the Haplopharyngida is arranged in mid-body and the female apparatus lies posterior of the male one. Usually, the distal male duct (stylet, cirrus, antrum masculinum) is directed more or less anteriad, however, all transitions from anteriad, laterad or posteriad orientation are present. The distal genital ducts of vagina and ejaculatory duct open to the exterior either separate as in Microstomidae, most of the Macrostomidae and Myozonidae, or in common, often via a common genital atrium, as in Siccomacrostomum and Dolichomacrostomidae. Greatest reduction of the female apparatus arises in Psammomacrostomum equicaudum to only a gonopore possibly being transient or even totally absent as in Myomacrostomum and Bradynectes. Fig. 12. Archimacrostomum rubrocinctum. A.-D. Groups of aflagellate spermatids in different developmental stages (after Hendelberg 1969). Testis Male gonads developed bilaterally (testes) or singly (testis), are lying mostly anterior to the ovaries. A position of testis and ovary side by side appears when both the gonads are developed singly or unpaired. Noticeably in some members of the genus Microstomum, the position of testis is latero-posterior to the male copulatory apparatus. The testis is compact and of sacular form and gives way to the vas deferens. The testis often reveals a zone of differentiation lying, e.g., latero-caudally as in Bradburia (Fig. 55, p.157) or rostrally and caudally as in Paromalostomum fusculum (Rieger 1971c, 1991). The testis of the Dolichomacrostomidae and Haplopharyngidae is lined by a thin extra cellular matrix and surrounded by somatic cells which also extend into it. The same appears in the ovaries, here, the extra cellular matrix is called tunica. Tunica cells, furthermore, separate often oocytes when maturing. Based on the evolutionary theory that more resources are allocated to sperm production when sperm competition is high (Parker 1998), Schärer et al (2004) tested the correlation of testis size and testicular activity in Macrostomum lignano. Testicular activity was measured through BrdU (5-bromo2 -deoxyuridine) labelling of specimens to estimate the number of testicular stem cells in S-phase; BrdU becomes only incorporated into cells when they are undergoing DNA duplication. Experimental treatments confirmed that testicular activity was significantly higher in specimens that develop in larger groups and thus have developed larger testes. Schärer et al. (2004) have shown that measuring testis size is a good measure of resource allocation to the male activity. Generally, spermatozoa of the species of the Turbellaria are biflagellate but in some taxa non-flagellate spermatozoa are present (cf. Watson & Rhode 1995). To the latter group (Fig. 12), evidently, all species of Macrostomida and Haplopharyngida belong (Hendelberg 1969, 1977, Rieger 1981, Sopott-Ehlers & Ehlers 2001). However, the spermatozoa of some of the fresh-water Macrostomida (some species of Macrostomum and Promacrostomum gieysztori) have developed peculiar lateral bristles (Ferguson 1939a, b). The bristles of Macrostomum tuba contain an electron-dense axis extending for some distance into the cytoplasm; tapering dense structures and associated striated plate-like structures are close to them (Rohde & Watson 1991). Rohde & Watson (1991) suggested these structures are modified flagella and 20

21 flagellar rootlets, respectively, but convincing evidence for this interpetation is lacking. These bristles are evidently not derived from flagella (Rieger 1981) because of absence of the ciliary nature (Bedini & Papi 1970, Ehlers 1985). Rohde & Faubel (1997), however, detected during the process of spermatogenesis axonemal (centriolar) structures in Paromalostomum fusculum, which likely resorbed during spermatogenesis. This fact could indicate that presence of centriolar structures supports the view that bristles of other macrostomids are derived flagellar structures as well (Rohde & Faubel 1997). Fig. 13. Spermatids of Paromalostomum fusculum (after Rohde & Faubel 1997). A. Diagram of cross (left) and longitudinal (right) sections of young spermatid. B. Early stage of spermatid with condensed chromatin and centrioles (ce) arranged at an angle to each other. C. Early stage of spermatid with centriole (ce). B. and C. Arrows point to microtubules close to centrioles. Fig. 14. Macrostomum sp. Thomas & Henley. Arrangement of cortical singlet microtubles of spermatozoa in the nuclear region. Axonemes are absent (after Thomas & Henley 1971). The longitudinal and cross section of a spermatozoon of Paromalostomum fusculum is given in Fig. 13A. The non-nucleated part of the spermatozoon is here called distal and the nucleated one proximal (Rohde & Faubel 1997). Particular attention should be given to the distal rod being of srew-like shape, and to the number of peripheral microtubules, which are gradually reduced distad. Peripheral microtubules appear in early stages of spermatid development near centrioles (Fig. 13B,C). Dense granules and microtubules, four to five per row at opposite sides of the cell, are only present in the distal part of the cells which are devoid of mitochondria. Mitochondria, round in cross section, surround the nucleus in a single or in several rows. The nucleus is strongly coiled in its most distal part and intracellular septa, possibly ingrowths of the cell membrane or endoplasmic reticulum, are distinct between rows of mitochondria. This basic pattern of macrostomid spermatozoa was also documented in sperms of Bradynectes sterreri Rieger, Myozona purpurea Faubel, Haplopharynx rostratus Meixner, Nynaeshamnia 21

22 turbanelloides (Karling) (Sopott-Ehlers & Ehlers 1998, 1999, 2001), and Macrostomum tuba v. Graff (Newton 1980, Rohde & Watson 1991). Thomas & Henley (1971) investigated the ultrastructure of the spermatozoa of Macrostomum sp. The results were that there are ca cortical singlet microtubules and these are the only microtubular components of the motile spermatozoa (Fig. 14). Free or incorporated axonemes are absent. Negatively staining with phosphotungstic acid (PTA) revealed the helical arrangement and the protofibrillar configuration of the subunits. One microtubule was observed to be made up of 12 protofibrils. The study of various stages in the transition from helical to protofibrillar configuration pointed to two steps in the conversion: a) seemingly random lateral separation of subunits forming protofribrils with a longitudinal periodicity of ca. 80Å, b) subsequent change in spacing of the subunits along the length of the protofibril, from ca. 80Å to Å. Ovary In the families of the Macrostomida and Haplopharyngida the ovary is dominantly disposed unilateral with the exception of species of the Macrostomidae. Ovaries are arranged in three characteristic patterns concerning fields of oogonia (germ cells) and successional strands of oocytes. The unilateral pattern disposes rostral oogonia followed by a single strand of oocytes in median, right or left line of the body. The ovaries of the Macrostomidae are dominantly disposed as separate bilateral fields of oogonia followed by strands of oocytes. Often the last oocytes of each strand come mediad in close contact just before they are received by the oviduct (spermatic duct). A third disposition is given in so far that oogonia grow up in more or less separate (bilateral) fields and the successional oocytes form caudad a single strand. Often the bilatery of oogonian fields are traceable only on serial sections. The bilatery or singularity of ovarian fields of ovaries is reckoned as character on genus level. The oogonia of the ovary accumulate autosynthetic yolk material, therefore, these gonads are called homocellular gonads producing oogonia entolecithally (Gremigni 1988). Distad, the oogonia grow up and differentiate to oocytes. The ooplasm of the oogonia is accumulated with membrane-bound oblong proteinaceous yolk globules produced by the endoplasmatic reticulum and Golgi complex. A lamellated cortex is sometimes visible around these globules. In maturing oogonia another type of globules is accumulated before proteinaceous yolk globules are produced (Meixner 1924, Ehlers 1985, Rieger 1981), interpreted as egg-shell Fig. 15. Microstomum lineare. A. Sagittal section through the ovary. B. Sagittal section through an uni-follicular ovary (after Meixner 1924). globules (Fig. 15, esg). The egg-shell globules were not observed to become cortically positioned. These interpretation is based on a positive test on polyphenols in form of silver 22

23 precipitate. Polyphenols are basic substances of egg-shells and result in sclerotinised shells through a tanning process (Gremigni et al. 1987, Gremigni 1997, 1988). In Macrostomum species, the egg-shell globules are of different shape and structure than that of dolichomacrostomids documented on studies of species of Paromalostomum by Smith et al. (1988). Species of Macrostomum display a peculiar mosaic pattern of more (polyphenols) or less (proteins) electron-dense areas (Gremigni 1988, 1997). Tunica cells often separate maturing oocytes. Maturing oogonia and oocytes are often accompanied by accessory cells which form a shield around the ovary and between the oogonia. As to the extracellular lamina around the ovary, Gremigni (1998) is of the opinion that either the peripheral accessory cells or the complex accessory cells plus the extracellular lamina correspond to the tunica described by former investigators on light microscopical level (Hyman 1951, Ax 1961, Luther 1960). Meixner (1924) described an aberrant development of Microstomum species (Fig. 15). Follicles contain only one single oogonium which develops to a mature oocyte. The other oogonia surrounding that oogonium become abortive. Accessory or abortive oogonia are also reported by Rieger (1971b,c) in the growth zone of Dolichomacrostomidae. Male Reproductive System The male reproductive system matches the part of the ejaculatory duct, vasa deferentia and testes. Accessory glandular and/or glandular muscular organs are common in members of the Dolichomacrostomdae. Completely developed, the ejaculatory duct consists of seminal vesicle, prostatic vesicle and penial stylet, cirrus or antrum masculinum. The ejaculatory duct could be ciliated throughout or in parts of his length (cf. Luther 1905, 1960, Ferguson 1939a, b, 1940a, Rieger 1971b,c, Doe 1986a,b). Often seminal and prostatic vesicle are joined via an intervesicular duct of variable form and length. Sometimes, the intervesicular duct is reduced to a small constriction marked by a distinct sphincter. The prostatic vesicle is developed as oval or globular vesicle with intra- or extravesicular prostatic glands. The distal Without charge, Elsevier (Oxford, UK) did not grant permission to use Fig. 22, Ferguson 1939c, and Figs 30 and 32, in Ferguson 1940a, in this context. Fig. 16. Ciliated chambers of the prostatic vesicles of Macrostomum shenandoahensis Ferguson, 1940 (A), Macrostomum reynoldsi Ferguson, 1939 (B), and Macrostomum truncatum Ferguson, 1940 (C) (after Ferguson 1939c, 1940a). parts (necks) of the glandular ducts are incorporated, often dilated, into the epithelium. The epithelium is commonly ciliated. After Rieger (1971a,b,c), Sopott-Ehlers & Schmidt (1974a) and Doe (1982), two different kinds of glands enter commonly the prostatic vesicle; three different kinds were reported from Haphlopharynx but only one from an unknown species called by Doe (1982) Macrostomum sp. The prostatic vesicle is distally either encased by the proximally dilated part of the stylet or joined via a more or less long prostatic duct to the proximal end of the stylet which here is usually not expanded. The prostatic vesicle is often divided into two areas (Fig. 16), a proximal one with several (mostly 4 to 5) ciliated chambers and a distal non-ciliated and non-chambered part filled with granulated material (Ferguson 1939c, 1940a). A reduced prostatic vesicle (Plate XIII: B,F,Hb), character of the genus Archimacrostomum, lacks a common wall and the distal glandular necks of the prostatic 23

24 glands are ampulla-like dilated and encased by the proximal funnel-like part of the stylet. A prostatic vesicle of species provided with an antrum masculinum is either absent (Antromacrostomum, Psammomacrostomum) or is continuous with the antrum masculinum (Myozona purpurea) or the cirrus is only marked by the different kinds of epithelia. Psammomacrostomum is characterised by a copulatory bulb of duplex type with a seminal prostatic vesicle into which the cirrus is invaginated comparable to the distinct family Fig. 17. Sagittal recontructions of stylets, connections to prostatic vesicle and epithelial ejaculatory duct of Archimacrostomum sp. Doe, (A), Microstomum sp. Doe, (B), and Haplopharynx quadristimulus Ax (C) (after Doe 1982, 1986a). character but of simplex type of the species of the family Convolutidae von Graff, 1904, Acoela. The seminal prostatic vesicle is characterised by a common lumen with a proximal compartment of sperm storage and distal glandular compartment lined either with a glandular epithelium or with an epithelium interspersed by necks of prostatic glands. Stylets are the dominant male organs in the copulatory systems of Macrostomida and Haplopharyngida. After the excellent studies on the ultrastructure (Doe 1977, 1982, 1986a,b, Brüggemann 1985, 1986b), it is known that stylets are not consisting of cuticular material, i.e. they are not extracellular products but stylets are intracellular specialisations within ringshaped matrix syncytia (Fig. 17). The matrix syncytium covers a distal part of the prostatic vesicle and is most prominent near the proximal end of the stylet. The matrix syncytium can be interpreted as specialised distal part of the epithelium of the ejaculatory duct (Doe 1982). The sclerotised parts of the stylets are formed from distal to proximal (Rieger 1968, Brüggemann 1986b). The final appearance of stylets could obviously be also a secundary process as observed during studies to the population dynamic of Microstomum papillosum (Faubel 1974). The stylet of fully mature specimen of M. papillosum is provided distally with 24

25 a hook-like bend turned at an angle of about 90 from the main axis. This bend is not to observe when the stylet is formed. First, completely developed, this distal hook-like bend is visible. A comparable secundary formation of the final outline of the stylet was not observed in Microstomum jenseni, Microstomum spiculifer and Microstomum bioculatum. The stylets form successively the final outline. The stylet apparatus of Haplopharynx quadristimulus (Fig. 17C) composed of a main central stylet and 5 accessory stylets (spines), contains 6 different cell types (Fig 17C) arranged ring-shaped around the distal ejaculatory duct. Two of which produce the main central stylet (cell-type 1 after Doe 1982) and the accessory stylets (cell-type 5). The sclerotic ultrastructure of the stylets consists of cross-striated microfibrillar material more conspicuously seen in the accessory stylets (Fig. 17C acs). In the main stylet the cross-striated structure is only clearly to see in the proximal one-half of the stylet whereas distad the striated structure fuse together to form a tube with nm thick walls (Doe 1986b). It is necessary to differentiate exactly between the anatomical terms penis, cirrus, and antrum masculinum and the term male atrium used in this monograph. In most cases the discrimination, if an antrum masculinum or male atrium is present, will be very complicated because of contraction and often contortion during the fixation process of specimens. Therefore, to come to a clear determination it is necessary, at first, to define the terms penis and cirrus. A penis is generally restricted to penis papilla, penis rod, or penial stylet. The penis papilla is a muscular projection that terminates the ejaculatory duct and is employed by simple protrusion to the exterior. The penis papilla varies from a mere eminence to a pronounced conical projection into an atrium or penial pocket. The penis rod is a rod-like muscular prolongation of the ejaculatory duct or of a penis papilla and is applied by forceful protrusion to the exterior. Up to now, that type of penis is not known within the Macrostomida. Commonly in the Macrostomida, the penial stylet represents a sclerotised, deformable (when pressing the cover slip) hollow tube that may be long or short, straight, curved, or coiled. A penis bearing a stylet or developed as stylet, is said to be armed. The stylet is used in the same manner as the papilla or rod, by protrusion. Distally, the penis projects into a ciliated male atrium if present or directly to the exterior. The term cirrus is limited to a distal ejaculatory duct which is employed by eversion to the exterior, i.e. by turning insight out. The cirrus never being ciliated, is either invaginated into a seminal or seminal prostatic vesicle (Plate XVI A-C: Psammomacrostomum equicaudum) or invaginated into a hollow muscular body called copulatory bulb (Plate XVI R) or only lined by outer muscle layers (Plate XVIII K). The walls of the cirrus are either glandular with intra- or extraepithelial prostatic glands (Fig. Myozona purpurea) or only epithelial, that are brought to the outer surface of the cirrus when it everts. Distally to the cirrus, often a ciliated atrium could be developed. The term antrum masculinum was established by Westblad (1945) and applied to tube-shaped ejaculatory ducts being ciliated (Plate XVI H: Antromacrostomum armatum), the walls of which are structured epidermis-like, containing intra- or extraepithelial glands, and the muscle sheath is similarly layered as the body wall muscle (Antonius 1968). The antrum masculinum lacks any penis or stylet armature and works cirrus-like. In that case a male genital atrium is absent. The male atrium is applied to the cavity, that extends between base of cirrus or penis and gonopore. It varies from a shallow depression to a spacious cavity or elongated tube and appears to evert partially during copulation. The epithelial walls and muscle layers are identical in histology with the adjacent body wall elements. On the basis of the outline of the male stylets of species of the genus Macrostomum, Beklemishev (1951) defined three distinct taxonomic species groups. Following the idea of Beklemishev for the application to the whole gender, it would become necessary to create a further characteristic group in relation to the outline of the stylet. That holds for all the species related to Macrostomum ruebushi which I have integrated into the Macrostomum orthostylum 25

26 group, provisionally. With the exception of the Macrostomum tuba group, the taxonomic use of these groupings became obsolete and fell into desuetude. All species of the genus Archimacrostomum were recruited from the Macrostomum hystricinum group. The definitions of the species groups according to Beklemishev (1951) are as following. Macrostomum hystricinum group Definition. Stylets with broad proximal basis, funnel-shaped, gradually tapering in diameter to the distal pointed tip; distal part of the stylet is bent hook-like; distal opening of the ejaculatory duct at level of hook-like bend (subterminal) (Plate V). Macrostomum tuba group Definition. Stylet slender, tube-shaped; distal part of stylet with terminal or subterminal opening; margin of opening bluntly thickened (Plate VI-VIII). Macrostomum orthostylum group Definition. Stylet tube-shaped, slender, distad more or less gradually tapering, with distal truncated terminal opening; distal opening not thickened (Plate IX- XI). With respect to stylets, in particular, of the Macrostomum hystricinum group, often it is unclear how measurements of the stylets were performed as to length and width. Therefore, it becomes necessary to determine an exact procedure for measuring male stylets of the Macrostomida. Appropriate methods were proposed by Ferguson (1940b) and Gehlen and Fig. 18. Methods of measurement of stylets of Macrostomidae. A. Method modified after Ferguson (1940b). B. Method exemplified by Gehlen & Lochs (1990). C.-D. Adaptation of the method after Gehlen & Lochs to the measurement of slightly flexed (C.) or straight stylets (D.). Lochs (1990). Both procedures could be used for the characterisation of the stylets. The method after Ferguson (1940b, p. 138, Fig. 27), in slight modification (see Fig. 18A), runs as follows. The stylet is characterised by three lines a, b, and c: line a is the diameter of the proximal opening, line b is erected perpendicularly on line a at point a/2, and line c is running from the distal tip of the stylet to that point where line b cuts the stylet wall. The flexed stylets differ through the angle of flexure of the lines b and c, angle α (Fig. 18A). The second method exemplified by Gehlen and Lochs (1990, Fig. 18B), presents the characteristic measurements of the lines a (ST w after Gehlen & Lochs) and d (ST L after Gehlen & Lochs) as following: line a (identical with line a of the method after Ferguson) is the diameter of the proximal opening of the stylet, line d is the distance between the distal tip of the stylet and the rearward border 26

27 Fig. 19. Macrostomum xiamensis. Outline of stylet in different strength of squeezing (modified after Wang & Lou 2004). Fig. 20. Diagrammatic illustration of the female copulatory ducts and closure apparatuses of species of the genus Macrostomum (after Luther 1947). A. M. thermale, B. M. boreale, C. M. balticum, D. M. hamatum. of the proximal opening (Fig. 18B,C). If the stylet is straight and not flexed - some species of the Macrostomum orthostylum group - line d is the distance between the most distal and proximal end. A third line e (diameter of distal opening) is here added because this measurement is often given in descriptions. In bent stylets the method of measurement is more appropriate after Gehlen and Lochs (1990). Generally, one have to take in mind that the real reproduction of the outline of stylets being flexed in different planes, depends on the strength of pressure, i.e. flattening through the process of increasing pressure of the coverslip as the preparation dries. That could be best demonstrated on Macrostomum xiamensis Wang (Fig. 19), Plate XI T: Macrostomum spirale, and in Bauchhenss 1971, p.617, Fig. 4A-C,F. Female Reproductive System The female reproductive system of the Macrostomidae matches the different parts of the female duct and ovaries, i.e. female pore, vagina surrounded by cement and/or shell glands, female atrium, common oviduct, or oviducts if ovaries paired. (Fig. 20). Oviducts and common oviduct are essentially extentions of the tunica of ovaries. Paired ovaries lie in a latero-ventral position behind testes. The single ovary if located in mid-ventral line, lies beyond gut. The transition from the common oviduct to the female atrium is often characterised by a cellular closure apparatus of so-called passage cells ( Verschlussapparat of German authors) consisting of tall cells and often provided with dilator muscles Fig. 20D. The closure apparatus depicted in Figs 20A- C, is comparable to the bursal mouth of Acoela. The female system of Dolichomacrostomidae strongly deviate from that of the other families Microstomidae, Macrostomidae, and Myozonidae. Mostly, from a common gonopore arises a genital atrium into which a vagina, bursal canal ( Bursastiel after Pawlak 1969), a sclerotised apparatus of the bursal organ, and a male ejaculatory duct enter (cf. Rieger 1971b,c). Within the Microstomidae the female copulatory apparatus is greatly reduced to a ciliated vagina into which shell glands open (Plate I: F). In Psammomacrostomum equicaudum and evidently in species of the Haplopharyngida only a female pore is present or transient. In P. equicaudum cement glands surrounding the inconspicuous female pore, open through the epidermis close to the gonopore (Plate XVI A). A female copulatory apparatus is 27

28 lacking in species of Bradynectes and Myomacrostomum. Members of the Myozonidae have a prominent access to the digestive system via a communicatio genito-intestinalis (Plate XVIII B,H,J). This genito-intestinal duct connects the oviduct with the caudal part of the gut. The duct can be open or close via a nozzle, sphincter, or tissue membrane as specified in Myozona psila. Cement glands are determined to open to the exterior through the epidermis around the gonopore and shell glands enter the lumen of the vagina. In Macrostomidae and Microstomidae only one type of that glands is present. The Dolichomacrostominae on the contrary have both types of glands with identical destination. As documented for polyclad shell-glands (Ishida & Teshirogi 1986) and umagillid cement glands (Ubelaker et al 1986), it is to assume that shell glands and cement glands of Macrostomida work upon the same pattern. Shell-glands discharge granules into the female duct and form egg-shells in interaction with egg-shell globules produced by the eggs itself. Cement glands surrounding the female gonopore, are responsible for producing stalks sticking to surfaces of substrates and capsules for the protection of the oocytes. Often cocoons are formed. The cocoons are deposited in clefts or lacunae of substrates or detached to those. Cocoons of Macrostomum romanicum could contain up to 20 eggs, which were formed in the vagina. The cocoon is expelled by peristaltic actions of the muscular vagina to the exterior whereat the body muscle wall remains continuously contracted (Ax & Borkott 1968). That process is initiated by bulging out of the ventral female genital region. Embryology and Postembryology Based on ultrastructural studies of the oogenesis in Macrostomum sp., Gremigni et al (1987) hypothesised that probably most archoophoran Turbellaria develop oocytes producing and accumulating autosynthetically yolk and shell globules. Endoplasmic reticulum and Golgi complex of maturing eggs produce more or less electron-dense vesicles the coalescence material of which give rise to two types of inclusions, i.e. egg shell globules containing polyphenols and tanned proteins, and protein yolk globules with homogeneous core and lamellated Fig. 21. Generalised scheme for the late embryo development of Macrostomum hystricinum and most of Neoophora (after Thomas 1986). A. Embryo before spreading of epidermis. B. Onset of spreading of the epidermis from a site near the developing brain. cortex (Gremigni 1988). Informations on the spiral cleavage of oocytes of Macrostomida were presented by Papi (1953) and Seilern-Aspang (1957) on Macrostomum hystricinum (Fig. 21). One hour after egg deposition two micromeres become visible in an equatorial position of the egg. The first cleavage is meridionally resulting in two blastomeres AB and CD of different size. CD undergoes another meridional almost equal cleavage giving rise to the macromeres C and D. 28

29 Fig. 22. Macrostomum hystricinum. Pattern of presumptive predispositions during cleavage (after Seilern-Aspang 1957). A. mature oocyte. B. 2-blastomere phase. C. 4-blastomere phase. E. Phase of hull cell spreading. F. Blastomeres covered with yolk mantle. G. Embryo in which blastema has begun spreading. The cleavage of AB undergoes asynchronously with levotropic displacement, giving rise to the two macromeres A and B. Macromere B is smaller than A. The third claevage proceeding asynchronously with dextrotropic displacement, results in eight macromeres. The macromeres A and B undergoes cleavage before C and D. Already at this stage the eight cell complex is no longer clearly determinable. All later cleavages are impossible to study in vivo (Papi 1953). Hatching occurs after three or four days. The cleavage of the early stages of Macrostomida is identical with the cleavage stages of polyclads. However, the process of gastrulation and late development of Macrostomum hystricinum differs from that of the 29

30 Polycladida after Seilern-Aspang (1957). At the 16-cell stage, 12 micromeres sink into four large, yolk-laden, vegetal blastomeres in an inverted epibolic process (Fig. 22E). These blastomeres flattened, surround the remaining blastomeres completely forming a yolk mantle or hull membrane (Figs 21, 22G). This process resembles strongly the development occurring within most of the neoophorans (Thomas 1986). The occurrence of these similar processes in the archophoran M. hystricinum and most neoophorans is of possible significance. Since it is during this late phase of development that a dorsal yolk mass is incorporated in both Macrostomum (yolk-filled blastomeres) and the Neoophora (yolk cells proper), it is possible that development in Macrostomum represents a preadaptation to ectolecithy. The developmental patterns observed, are generally compatible with the phylogenetic diagram of the orders of Turbellaria proposed by Karling (1974a) (Thomas 1986). Reisinger (1923) reported on the development of twins in Macrostomum hystricinum Beklemishev and Macrostomum viride van Beneden. The twins of macrostomids arose mostly from two fecundated eggs positioned into one egg shell. Another possibility Reisinger suggested that both the first blastomeres of a single fecundated egg are separated and individually develop to monozygotic twins. Cytology, Cytochemistry. Neoblasts (stem cells) are totipotent, undifferentiated cells from which all somatic cells are derived through the process of proliferation (Rieger et al. 1999). Macrostomum lignano is used as model system to study stem cell biology of flatworms (Pfister e al. 2007). Throughout the life of an organism, neoblasts retain their capability for proliferation. After Ladurner et al. (2000) and Nimeth et al. (2004), Macrostomum lignano has about 25,000 cells of which 20% can be considered to be neoblasts or neoblasts in differentiation. Spatial differentiation revealed that neoblasts, S-phase cells and mitotic cells, labelled with BrdU (5 - bromo-2 -deoxyuridine) in 30-min pulse and up to 4h chase experiment, were distributed in two bands along the lateral sides of the body. Median parts of body and the region anterior to the eyes remained unlabelled. At longer chase times, clusters of labelled cells appear in the unlabelled areas, obviously, as a result of division of labelled cells and migration into the areas of the median axis and regions anterior to the eyes (Rieger et al. 1999, Ladurner et al. 2000, Nimeth et al. 2004). The smaller amount in regenerated head parts, however, could be explained partly by cells in G 2 -state and partly by morphallactic processes. The pre-existing G 2 -cells differentiate in the first place without being labeled with this method (cf. Palmberg 1990 in Microstomum lineare). Decapitation evidently activates free neoblasts in G 2 -state demontrated by an early peak of mitotic activity during regeneration (Morita & Best 1984, Saló & Baguña 1984). Immunocytochemical studies have also been made by Reuter and collaborators on stem cells to reconstruct the nervous system of Microstomum lineare (for references see chapter Nervous System). Starvation and feeding experiments on Macrostomum lignano were performed by Nimeth et al. (2004) to determine the dynamic of the mitotic activity (number of mitoses). Starvation, generally, reduces body size and gonadal activity accompanied by a decline of the number of mitoses. After 30 days of starvation, the animals decreased by about a third of the body length, the gonads and copulatory organs had disintegrated, and the number of somatic mitoses decreased to 0.74 ± Feeding with diatoms resulted in a fast increase of recovery of proliferating cells. The number of mitoses increased 5.5-fold after 30 min. (4.20 ± 2.9; n = 10) and 55-fold after 6h (41.00 ± 8.6; n = 9) of feeding. After 12h the number of mitoses had decreased to ± 7.5 (n = 10) and increases again to a maximum of ± 19.5 (n = 11) mitoses after 48h feeding time. The initial increase (until 6h) evidently were based on 30

31 neoblasts arrested in G 2 -state. The depletion of this G 2 -pool resulted in the decrease of the number of mitoses observed. Behensky et al. (2001) have been developed a fluorescence method to stain cell suspensions from Macrostomum lignano and Dugesia tahitiensis Gourbault, 1977 (Tricladida) with acridine organge placing special emphasis on the characterisation of neoblasts. The neoblasts of both species stained, yielded identical staining patterns. The staining with acridine orange of single stranded RNA and intact double stranded DNA revealed red phosphorescence of RNA and green fluorescence of DNA. Under proper conditions (Darzynkiewicz & Kapuscinski 1990, Watson 1991) denaturing of RNA kept DNA in double stranded form. The method should facilitate monitoring the heterogeneity of the neoblasts compartment as well as studying cellular dynamics during growth, regeneration and other physiological processes (Behensky et al. 2001). Nothing is known to the programmed cell death within free-living Turbellaria. Investigations to apoptosis and cell renewal were carried out by Nimeth et al (2002) in Macrostomum lignano. Cell renewal of epidermal cells is already longer known from observations of replacement cells ( Ersatzzelle of German authors) seen in serial sections of individuals studied under the light microscope (Tyler 1984). Apoptosis of parenchymal cells of Macrostomum lignano was confirmed by a high turnover of cells labelled with BrdU (Nimeth et al 2002). Apoptosis is a very fast process (Willingham 1999); Nimeth et al. (2002), however, found that only 20.8 cells per hour were phagocytosed in their experiments. They assumed that other degradation mechanisms than apoptosis play an additional role in the elimination of cells. Generally holds, maintenance of tissue is achieved only if apoptosis and cell proliferation are precisely balanced. Self-fertilisation, Asexual Reproduction Sekera (1906) hypothesised that parthogenesis or self-fertilisation is common among microturbellarians. Results reported by Rieger et al. (1988), confirmed the observations of Sekera. Based on culture experiments, isolated juveniles of Macrostomum hystricinum marinum Rieger became sexually mature and laid eggs. Ax & Borkott (1969) observed that cross fertilisation did occur in Macrostomum romanicum Mack-Firă. Hyman (1951) emphasised that Fig. 23. Species of Macrostomum fertilisation, from live observations. in cross mutual insemination is the rule among the rhabdocoels (Fig. 23). Culturing species in petri dishes, cross fertilisation was generally observed not only in sexually mature acoelous species but also in diverse species of Macrostomida (Macrostomum balticum Archimacrostomum pusillum, M. tuba, Myozona purpurea, and Paromalostomum fusculum) during copulation when both partners are sexually well developed (Apelt 1969, Faubel unpubl.). Within the Macrostomida, asexual reproduction follows the type of paratomy by fissioning, i.e. after rebuild of the organs the fission occurs. Architomy as reproduction form is not known. Wagner (1890) defined the term paratomy in Microstomum lineare. Within the Archoophora fissioning is more described in members of the Catenulida (cf. Moraczewski 1977) than in members of the Macrostomida (von Graff , Ruhl 1927, Meixner 1938, Hyman 1951, Beklemishev 1958, Henley 1974). Within the Macrostomida paratomy is only known from species of the Microstomidae and Myomacrostomum Rieger. The paratomy present in the members of the genus Myomacrostomum, give rise to Rieger (1986) for a 31

32 discussion of phylogenetic conditions within the taxon Macrostomida. Asexual reproduction was interpreted as primitive character (Rieger 1986) and secondary development of turbellarian life cycle (Ax & Schulz 1959). Dominant reports were mostly given on Microstomum lineare. The only electron microscopical studies were made by Reuter & Palmberg (1983, 1987) and Palmberg (1990) on Microstomum lineare. In asexually reproducing M. lineare, Reuter & Palmberg (1983) and Palmberg (1990) studied autoradiographically and ultrastructurally the distribution of proliferating cells. Mesenchymal and gastrodermal neoblasts (stem cells) labelled with tritiated thymidine, were distributed along the whole worm without any special growth zones or axial gradients. Organ primordia arise from locally dividing as well as immigrated cells. Activation of cell proliferation and migration may be controlled by the nervous system. The release sites of peptidergic nervous influence seem to be synaptoids and omega-shaped configurations which are observed at muscles of the division zone and in the vicinity of migrating cells. Reuter & Palmberg (1983) demonstrated that peptidergic nerve fibres Fig. 24. Diagrammatic reconstruction of the division zone (dz) in Microstomum lineare. Peptidergic transverse nerve fibres (tnf) between septum muscles (sm) joined by longitudinal nerve fibres (ldf) and nerve swellings (nsw) (after Reuter & Palmberg 1983). dominate in the division zones of Microstomum lineare, emphasising the significance of this part of the nervous system. The peptidergic nerve fibres form a circumferential belt. Longitudinal nerve fibres and nerve swellings (Fig. 24) join the circumferential belt from opposite directions. Mature zooids separated by muscle contractions are controlled by the nervous system. 32

33 To what extent growth factors influence asexual reproduction in lower turbellarians, inter alia Microstomum lineare, Reuter & Kuusisto (1992) tested the immunoreactivity to vertebrate epidermal growth factor receptor (EGF-r), epidermal growth factor (EGF) and basic fibroblast growth factor (bfgf) (Gustafsson & Eriksson 1992, Fairweather & Skuce 1995, Gustafsson et al. 1995). The experiments revealed growth-factor-like substances in cells near ciliary pits, the beginning of lateral nerve cords, and in the pharyngeal connective ganglia of asexually reproducing Microstomum lineare. Antibodies to the growth factors blocked asexual reproduction (Reuter & Kuusisto 1992). Immunoreactivity to all three antibodies occurred in the nervous system. Factors influencing asexual reproduction in form of fissioning, were generally reiterated on triclads (cf Rieger 1986). Westblad (1952) found that the marine Microstomum rubromaculatum reproduces exclusively by transverse fission. Henley (1974) stated in slight modification after Hyman (1951) that more commonly, in the freshwater forms at least, asexual reproduction appears to be the rule only until the advent of sexual maturity (often in autumn), when fission usually (but not always) ceases and sexual reproduction occurs. Regeneration Regeneration processes within Macrostomida occurs mainly by morphallaxis and are based on proliferation and differentiation of totipotent cells, called stem cells, which are able to mend wound tissue and to initiate or stimulate blastema formation, i.e. postembryonic proliferation, growth, tissue homeostasis and regeneration (Baguña 1981, 1998, Ehlers 1985, Drobysheva 1991). Stem cells were formerly called replacement cells, reserve cells, betacells, free-cells, germinative cells, or more recently neoblasts. In fission or regeneration processes stems cells are stimulated to divide, differentiate, and migrate to sites of repair. Stem cells split by mitotic cleavage unlike somatic cells, a cleavage of which was never observed (cf. Ehlers 1985). Investigations on stems cells of Macrostomida were performed by Palmberg (1986, 1990, 1991), Palmberg & Reuter (1983), Reuter & Palmberg (1983, 1987, 1989), and Reuter & Kreshchenko (2004) on Microstomum lineare and by Ladurner et al (1998, 2000), Peter 2001, Bode et al. (2006) Egger et al. (2006), and Nimeth et al. (2006) on Macrostomum lignano. In these studies tritiated thymidine or thymidine analog 5-bromo-2 - deoxyuridine (BrDU) was used for the identification of migrating and dividing cells. The only cells which incorporate tritiated thymidine, were neoblasts in the mesenchyme and gastrodermis proliferating continously to replenish the pool of stem cells available for regeneration, asexual reproduction and generally for growth. Regeneration after amputation or decapitation is initiated by a strong increase of immunoreactivity for FMRF/RF-amide in the injured nerve ends unlike the immunoreactivity for 5-HT at this stage, which was much weaker (Palmberg 1991, Nimeth et al. 2007). Two forms of proliferative cells have emerged (Palmberg 1991), one with and one without ciliary basal bodies. Neoblasts with basal bodies appeared in early stages of development (1 6 h), evolve into cell types with cilia, i.e. epithelial cells, flame cells, nerve cells, and sensory cells. Bode et al. (2006) identified three populations of proliferatung cells: somatic neoblasts (mesodermal neoblasts), gastrodermal neoblasts, and gonadal S-phase cells (testes and ovaries). Three stages indicated 2, 2-3, and 3 - of mesodermal neoblasts could be defined by their ultrastructure. The share in mesodermal neoblasts amounted to 6.5% of the total number of cells, 27% of these neoblasts were labelled in S-phase. Gonadal cells have a share of approximately 0.4%. Immunogold-labelled sections exhibited 70% of S-phase cells in direct contact or within 5µm distance from nerve cords (cf. Reuter et al 1984, 1986, 1995). Neuropeptid F-positive cells connected by a network of immunoreactive nerve fibres meandering in the intestinal wall, were observed in Microstomum lineare, using confocal microscopy. The pattern of these cells associated with the brain and pharyngeal nerve ring, 33

34 and the pattern of immunoreactive fibres in the nerve cords and intestinal wall correspond to that in FMRF-amide/RF-amide immunostaining. Immunoreactivity to neuropetid F and RFamide was substantiated in a cell pair (Fig. 6) in the rear end of mature zooid chains, which apparently marks the finished development of a new zooid (Grahn et al. 1995). Ingole & Shirgur (1985) observed in mass cultures of Macrostomum orthostylum that tail portions get detached during the release of large subitaneous eggs. Therefore, regeneration processes in form of recovery of cut portions were performed on specimens cultured in the laboratory. Regeneration of epimorphosis and morphallaxis type was observed only in specimens greater than 0.4mm. Recovery of the anterior portion (epimorphosis type) proceeded faster than that of the posterior portion. Replacement of the portion at the anterior end was finished after five days. The regeneration of the posterior portion followed the type of morphallaxis. After eleven days the posterior portion regenerated to a juvenile specimen. Other regeneration experiments (type of epimorphosis) were performed at the anterior body end. A cut just posterior to the eyes resulted in replacement of the lost portion within few days. However, detachment of only one eye resulted indeed in a complete recovery of that portion but without replacement of the detached eye. Regeneration was not observed anterior to the cerebral ganglion. Karyology Karyological investigations are of importance for questions of speciation and of the evolution of chromosomes. Chromosome numbers of several species were determined with phocus on karyometric analysis and idiograms, i.e. beta-level karyology according to the classification of White (1978), as opposed to alpha-level karyology in which only numbers of chromosomes are reported (Galleni & Puccinelli 1986). As to gametogenesis and chromosome pattern it is referred to Benazzi & Benazzi Lentati (1976) presenting an Fig. 25. Phases of mitotic and meiotic chromosomes of Macrostomum hustedi Jones (after Jones 1944). overview of studies on Turbellaria up to Of interest are the studies of Jones (1944) on Macrostomum hustedi, reporting a chromosome number of somatic cells of 12 (suggesting polyploidy) and bivalents from 2 to 6 (Fig. 25, Tab. 1); probably only the gametocy with 6 34

35 bivalents (2n = 12) develop normal gametes. With the exception of Macrostomum hystricinum (after Luther 1905, 1947) and Macrostomum thermale (2 bivalents) and Microstomum bispiralis and Macrostomum lignano (8 bivalents), all Macrostomida studied up to date, were found with 3 bivalents (Tab. 1). The number of 8 bivalents in M. spiralis and M. lignano contrasts markedly from the low numbers generally found in Macrostomida (Benazzi & Benazzi Lentati 1976, Egger & Ishida 2005). Tab. 1. Chromosome numbers in the Macrostomida. species chromosome number author 2n n polyploid Archimacrostomum beaufortensis 6 3 Ferguson 1940c Macrostomum bulbostylum = tuba 6 3 Ferguson 1940c Macrostomum crenatostylum 6 3 Ferguson 1940c Macrostomum fergussoni 6 3 Fergusson 1939a Macrostomum finnlandensis 6 3 Luther 1947 Macrostomum gabriellae 3 Marcus 1949 Macrostomum granulophorum 6 3 Ferguson 1940c Macrostomum hustedi 2 to 6 12 Jones 1944 Macrostomum hystricinum 2 (?) Luther 1905, 1947 Macrostomum hystricinum 6 3 Ferguson 1940c Macrostomum lewisi 6 3 Ferguson 1940c Macrostomum lignano 8 Egger & Ishida 2005 Macrostomum orthostylum 4 (?) 2 (?) Ferguson 1940c Macrostomum phillipsi 6 3 Ferguson 1940c Macrostomum reynoldsi 6 3 Ferguson 1940c Macrostomum riedeli 6 3 Ferguson 1940c Macrostomum shenandoahense 6 3 Ferguson 1940a Macrostomum tenuicauda 6 3 Luther 1947 Macrostomum thermale 2 Reisinger 1933 Macrostomum truncatum 6 3 Ferguson 1940c Macrostomum tuba 6 3 Phillips 1936 Macrostomum var. gigas 6 Yamamoto et al Macrostomum virginianum 6 3 Ferguson 1940c Microstomum bispiralis 16 8 Stirewalt 1937 Promacrostomum gieysztori 6 3 Papi 1951b Velamacrostomum glochistylum 6 3 Ferguson 1940c Molecular Analysis Body and genome sizes were estimated by Gregory et al. (2000) in 38 plathelminth species. Significant relationships could be found between genome size and body size, i.e., cell volumes show a positive allometric variation with genome size if cell volume shifts alone were responsible for variation in body size. The relationship between body size and genome 35

36 Tab. 2. Diploid genome and body size. Minimum and maximum values given, measured within the 38 analysed turbellarian species. (pg = picogram) species genome size (pg) body size mm³ Stenostomum brevipharyngeum (Caten.) Macrostomum sensitivum Microstomum lineare Macrostomum gilberti Otomesostoma auditivum (Proseriata) size of Plathelminthes analysed, resulted in a slope of 1.7 and the genome sizes measured, ranged from 0.12 pg (minimum) to pg (maximum). The measurements of three Macrostomida resulted in values between 0.34 pg (Macrostomum sensitivum) and 1.16 pg (Macrostomum gilberti) (Tab. 2). Gregory et al. (2000) suggested that changes in genome size could play an important role in explaining the enormous morphological diversity of invertebrates. Tab. 3. List of macrostomid species used for molecular analyses. species GenBank topic author(s) accession number Microstomum lineare D85092 phylogeny Katayama et al U70082 phylogeny Carranza et al AY phylogeny Ruiz-Trillo et al AJ phylogeny Littlewood et al AJ phylogeny Telford et al AJ phylogeny Telford et al AF phylogeny Littlewood et al Microstomum papillosum AF phylogeny Litvaitis & Rohde 1999 Macrostomum hystricinum AF phylogeny Carranza et al. unpubl. Macrostomum lignano AY homeobox protein Bebenek et al Macrostomum tuba phylogeny Rohde et al U70080 phylogeny Carranza et al D85091 phylogeny Katayama et al Macrostomum sp. L41127 phylogeny Rohde et al Paromalostomum fusculum AY phylogeny Lockyer et al Paromalostomum fusculum AJ phylogeny Littlewood et al 1999 Paromalostomum fusculum AF phylogeny Litvaitis & Rohde 1999 Microstomum sp. meiofaunal identification Litvaitis et al Molecular characters were and are further on being used to test both the mono- or polyphyly of Plathelminthes and to create the phylogenetic tree of the Plathelminthes independently of morphological and developmental features. Sequencing of 18S rrna was considered to be useful in testing and creating phylogenetic aspects not only within the 36

37 Plathelminthes but also within the procarotes and eukaryotes (Field 1988). The first attempt to trace the origin and phylogeny of Plathelminthes based on molecular analyses of species of Tricladida, Typhloplanida, and Trematoda, were performed by Riutort et al. (1993). Later on, Littlewood et al. (1999) concluded that the sister group of the Neodermata is the Neoophora forming a valid clade. The Polycladida, Macrostomida, and Haplopharyngida, basic members of the Rhabditophora, are monophyletic taxa. The monophyly of Seriata is invalid as well as the validity of the Trepaxonemata. For examination of questions to the phylogenetic relationships among turbellarian orders, sequence analyses of Macrostomida were only made from few species (Tab. 3). Litvaitis et al. (1994) used the molecular approach for the identification of meiofaunal turbellarians and among other species they analysed the sequence of a 284 base pair-long region of the 26/28S rrna from Microstomum sp. (nom. nud.). To date, the molecular data given in Tab. 3, are the only available data on Macrostomida. Phylogeny The investigations on the ultrastructure of the Turbellaria (Ehlers 1985) proved the paraphyly of the Archoophora encompassing the Acoela, Nemertodermatida, Catenulida, Macrostomida, Haplopharyngida, and Polycladida. Archoophora were characterised through the development of entolecithal eggs. Ectolecithal eggs were produced by all the other platyhelminths, the Neoophora. Ehlers (1985) combined Acoela and Nemertodermatida to the monophyletic taxon Acoelomorpha and Doe (1986a) combined the taxa Macrostomida and Haplopharyngida to the taxon Macrostomorpha. The Acoelomorpha and Catenulida are the most basal taxa and represent the sister group to the Rhabditophora which encompasses all the other plathelminth taxa (Fig. 26). After Rieger et al. (1991a) based on ultrastructure and Catenulida Acoelomorpha Rhabditophora Fig. 26. Phylogenetic concept of Plathelminthes after Smith et al. (1986), Ax (1995b) and Haszprunar (1996). Littlewood et al. (1999) based on morphology and molecular analyses, Polycladida, Macrostomida and Haplopharyngida are monophyletic within the Rhabditophora as are the last two taxa. One statement made by Littlewood et al. (1999), is, however, that it is stressed that morphological and molecular data in some respects lead to contradictory results. The Acoelomorpha, i.e. Acoela and Nemertodermatida, represent a sister group of the monophyletic group of Macrostomorpha being the basic phylum of the monophylum Rhabditophora. Following reasons do argue for a close relationship of Macrostomida and Acoela. The homology of biflagellate spermatozoa of Acoela and Rhabditophora (Rieger et al. 1991a). The presence of frontal or cephalic glands and rhabdites containing two rods (Glanduloposthia bruneorhabditis gen. et sp. n. Acoela, ms in prep.), found in a new acoelous species in Australia. Another indication is a true intestine found in Archiproporus philippinensis sp. n., Acoela (ms in prep.) at beaches around Mactan Island, Cebu, Philippines. The homology of the copulatory organs equipped with an antrum masculinum or cirrus of the acoelous species could be documented (Convoluta convoluta (Abildgaard, 1806), 37

38 species of the genus Praeconvoluta Dörjes, 1968, Convoluella Faubel, 1974, species of Antroposthiidae Faubel, 1976) and of the macrostomid species (Antromacrostomum armatum Faubel, Nynaeshamnia turbanelloides (Karling), Dunwichia arenosa Faubel, Blome & Cannon, and Unsia suaedae Bulnes). The macrostomid species mentioned, represent definitely a plesimorphous status within the Macrostomida based on the property of an antrum masculinum or cirrus in the male system. N. turbanelloides and D. arenosa are provided with a copulatory apparatus of simpex-type as it is also known within the Acoela. In addition, the female system of D. arenosa is equipped with a syncytial seminal bursa as it is likewise common within the Acoela. Conspicuously, all the species were found in deeper sediments of sandy beaches close to the coastal ground water table, the exception being only the species Convoluta convoluta. All the other genera of the Macrostomidae are provided with a sclerotised stylet. Therefore, the Macrostomidae represent a very heterogeneous taxon which will need a taxonomic revision (Rieger 2001). Up to now, there is no character known, which documents the monophylum of the Macrostomidae (Ax 2008). A possible calculation of the phylogenetic relationships of the Macrostomorpha was given by Sopott-Ehlers & Ehlers After that only the Microstomidae, Dolichomacrostomidae, Myozonidae, Bradynectes, and Macrostomum represent monophyletic taxa (Fig. 27). Fig. 27. Phylogenetic relationships within the Macrostomorpha (after Sopott-Ehlers & Ehlers 1999, p. 113, Fig. 6). Black squares represent hypothesised autapomorphous characters: 1. lamellated rhabdites, pharynx simplex with prominent nerve ring; 2. spermatozoon without ciliary axonemes; 3. cranial protrusible proboscis, specialised male organ (cf. Doe 1986); 4. female pore anterior to male pore, spermatozoon with two sets of cortical microtubules; 5. preoral blind sac of gut, ciliated pits at level of brain; 6. bursal organ with sclerotised elements, accessory glandular organ; 7. spermatozoon with bone-shaped rods, one cylindrical mitochondrial rod, and four sets of microtubules; 8. spermatozoon with two lateral leges; 9. wihtout female pore, spermatozoon with membranous lacunae; 10. protonephridia with twocell terminal weirs showing two rings of interdigitating microvilli; 11. protrusible muscular composite pharynx with pharyngeal cavity. 38

39 Systematic Account Order Macrostomida Meixner, Family Microstomidae Luther, Genus Microstomum Schmidt, Genus Myozonella Beklemishev, Genus Alaurina Busch, Genus Einarmicrostomum gen.n. 63 Family Macrostomidae van Beneden, Genus Macrostomum Schmidt, Genus Antromacrostomum Faubel, Genus Archimacrostomum Ferguson, Genus Bradburia Faubel, Blome & Cannon, Genus Bradynectes Rieger, Genus Dunwichia Faubel, Blome & Cannon, Genus Haplomacrostomum gen.n. 161 Genus Myomacrostomum Rieger, Genus Nynaeshamnia gen. n. 164 Genus Omalostomum Van Beneden, Genus Promacrostomum An Der Lan, Genus Psammomacrostomum Ax, Genus Siccomacrostomum Schmidt & Sopott-Ehlers, Genus Unsia Bulnes, Genus Velamacrostomum gen.n. 173 Family Myozonidae gen. n. 176 Genus Myozona Marcus, Genus Frisiazona gen. n. 180 Genus Myomarcozona gen. n. 181 Genus Australomyozona gen.n. 182 Family Dolichomacrostomidae Rieger, Subfamily Dolichomacrostominae Rieger, Genus Dolichomacrostomum Luther, Genus Austromacrostomum Rieger, Genus Cylindromacrostomum Rieger, Genus Megamorion Rieger & Sterrer, Genus Meiocheta Rieger, Genus Paramacrostomum Riedel, Genus Paromalostomum Meixner in Ax, Subfamily Karlingiinae Rieger, Genus Karlingia Ferguson, Genus Acanthomacrostomum Papi & Swedmark, Genus Myozonaria Rieger, Genus Paramyozonaria Rieger, Genus Riegerizonaria gen. n. 214 Subfamily Bathymacrostominae Faubel, Genus Bathymacrostomum Faubel, Genus Mactanea gen. n. 218 Species dubiae

40 Species incertae sedis 51,140,165,216 Nomina nuda 64,147,117,188,199,213,217 Order Haplopharyngida Karling, Family Haplopharyngidae Karling, Genus Haplopharynx Karling, Order Macrostomida Meixner, 1924 Diagnosis. Platyhelminthes with pharynx simplex and simple, straight, ciliated gut. Brain not encapsulated, crescent-like, immediately before mouth opening; without statocyst. Eggs entolecithal; female gonopore anterior to male one if genital pores separate; testes compact, male canal passes directly posterior to gonopore, usually with hard stylet. Free-living; marine, brackish and freshwater habitats. Key to the families of Macrostomida 1 progenies only sexually produced 2 - progenies sexually and asexually (paratomy) produced Microstomidae 2 female apparatus simple; sclerotised bursal organ absent 3 - female apparatus complex, with sclerotised bursal organ Dolichomacrostomidae 3 muscle ring on gut absent Macrostomidae - muscle ring on gut present Myozonidae Family Microstomidae Luther, 1907 Diagnosis. Macrostomida with pre-oral blind sac of gut. Ciliated pits at level of brain. Asexually produced discrete zooids (chains) as well as sexual reproduction. Male copulatory complex with tubular stylet; male canal passes behind male pore to enter pore from posterior. Gonopores separate. Ciliated sensory pits near front of body; frontal glands below brain present. Marine, brackish, and freshwater habitats. Type of the family: Microstomum Schmidt, 1848 Remarks. The pre-oral blind sac of gut and the cranial ciliated sensory pits are interpreted as autapomorphous characters. On the other hand, the asexual production of discrete zooids, paratomy by fissioning, is interpreted as a plesiomorphous character (Rieger 2001). As already outlined by Westblad (1953) and Faubel (1974) only 12 microstomid species of the totally known 24 species were described being sexually mature. Full sexual maturity will be completed only in solitary specimens. In asexually produced well developed zooids, genital organs start to develop but first in solitary individuals that developmental process will be finished. As to the development of stylets, a thorough probability will be that all stylets developed during chaining, most ones did not have received their full outline. A good example for that is the development of the stylet in Microstomum papillosum (cf. Faubel 1974). Key to the genera of Microstomidae 1 without proboscis-like fore-body 2 - with proboscis-like fore-body, planctonic Alaurina Busch p

41 2 single vagina present 3 - second vaginal duct present Einarmicrostomum gen. n. p with muscle ring on gut Myozonella Beklemishev p without muscle ring on gut Microstomum Schmidt p. 37 Genus Microstomum Oersted, 1843 Diagnosis. Microstomidae without proboscis-like fore-body. Seminal prostatic vesicle present. Bilateral testes and single ovary. Testes located posterior to ovary. Type of the genus: Fasciola linearis Müller, 1773 Remarks. The members of Microstomidae reveal two modes of reproduction, asexual fission producing chains of several zooids, and sexual reproduction. The period of sexual reproduction mostly takes a very short time - often not more than two weeks per year - within the life cycle (Figs 88-89) and is only related to solitary specimens. That is the reason why only 14 of a total of 39 species were described on the basis of genital organs. Based on the uncertain validity, all incompletely described sexually immature species are transferred to the category species incertae sedis. Microstomum lineare (Müller, 1773) Oersted 1843 (Plate I: A; Figs 3, 6, 10, 15, 24, 89; Tabs 2, 3, 4, 10) Synonymy. Fasciola linearis Müller, 1773 ; p. 67. Planaria linearis: Müller 1776; p Planaria vulgaris Fabricius, 1826; p , pl. I lit. C: figs 1-2. Derostoma leucops (in part) Dugès, 1828; p.141, pl. IV: figs 4, 27. Derostoma flavicans Ehrenberg, 1831; fol. b. Smigrostoma littorale Ørsted, 1845; p. ; Tab. 4: Schmidt 1848; p. 56, pl. VI: fig. 17. Microstoma flavicans: Schultze 1849; p Planaria falcata Dalyell, 1853; p , pl. XVI: figs Anotocelis flavicans: Diesing 1862; p Microstomum littorale: Diesing 1862; p Microstomum spec. Semper, 1876; p Microstomum giganteum Hallez, 1878; p Microstomum inerme Zacharias, 1894; p. 83. Type locality. unknown; types: not prepared. Habitat. Littoral benthal and phytal, sand, mud, algae, aufwuchs (Hydrozoa: Hydra sp., Cordylophora sp.; Bryozoa: Plumatella sp.), down to 52m water depth, eurytherm, eurytopic, lotic and lentic freshwater, brackish water. Salinity tolerance of up to 7 (Karling 1974). Geogr. distribution (cosmopolitan). EUROPE: Austria (Wörthersee, Lunz, Neusiedlersee, river Danube), Belgium, Bulgaria (Sophia, Plovdiv), Czechia (Prague, Břeclav), Danmark (Furesø, Dam I Bøndernes Hegn, Lyngby Sø, Dam ved Vrum Mose, Søndersø, Copenhagen), Estonia (Dorpat, Lake Peipus), Spain (rivers of Guadarrama Mountains, Guadalajara: Río Aliendre; Extremadura), Finland (from south to arctic circle), France (Lille, Montpellier, Straßburg), Great Britain (Lochs Lochend and Tay Lomond; Millport, Bennet s Lough, and 32 waterbodies see Young 1970, North Wales, western Midlands), Germany (Baden- Württemberg: Istein, Elbe Estuary, Hamburg: Süderelbe, Schleswig-Holstein; Berlin; south of Lower Saxony; area around Göttingen; Hesse: Marburg, pool in Botanic Garden, Aschaffenburg, Giessen; Thuringia: Jena, Mühlhausen/Bad Langensalza; Saxony-Anhalt: Axien; Bavaria: Franconia, Würzburg, Landshut, Bodensee, Mindelsee, Schleinsee, 41

42 Degersee), Hungary (Pancsova), Ireland (Co. Tipperary: River Shannon, Co. Wicklow, Co. Cork), Italy (Lago Maggiore, Monti d Oltreserchio: Fosso Contesora; Pisa; Lago di Garda, Lago di Loppio, Laghezza d Ampolla), LT ( Vilnio), Latvia (Dorpat), Makedonia (Lake Ohrid), Switzerland (Neudorf, Kleinhüningen and Augustinerholz near Basel, Geistsee, Thuner See, Lake of Geneva: Morges, Corsier, Lac de Neuchâtel: Yverdon, Lago Maggiore: Locarno), The Netherlands (Bergumermeer Lake, Brandemeer Lake, De Leijen Lake, De Veenhoop, Fluessen Lake, Heegermeer Lake, Koevorde Lake, Langweerderwielen Lake, Morra Lake, Oorden Lake, Pikmeer Lake, Prinsenhof Lake, Scheldt estuaries, Slotermeer Lake, Sneekermeer Lake, Tjeukemeer Lake, Wijde Ee Lake, Wijde of Peanster Ee), Poland (Grzymalow, Warsaw, Harsz-Lake, Wigry-Lake, Kraków, Lake Zbęchy, freshwaters of Prussia), Romania (Razemul Mare: Sinoe, Golovitza, Portitza, Dolosman; Siut-Ghiol Lake; Filipoiu Canal: Brăila-Balta; Bukarest: lakes Snagov, Mogoşoaïa, Herăstrău, Cluj Napoca), Russia (RU-KGD, RU-C: Moscow, Kaluga, Kazan, Vladimir, RU-E: Orenburg, Perm, Orlov, Krestov, RU-N: Solovetskiye Ostrova, Kolskiy Poluostrov, RU-W: Gouv. St. Petersburg, Novgorod, Vladimir Volynskiy, RU-S: Gouv. Orenburg, Saratov: Volga river, Kharkov, Poltava, Medveditza) Siberia: Angara, Lake Baikal), Ukraine (Charkov); BAL: Gulf of Finland (from area of Tvaerminne to St. Petersburg), Germany (Kieler Bucht: Bottsand; Vitter and Schaproder Bodden; Greifswald: Ryk), Sweden (Södermanland: Nynäshamn), Poland (Gulf of Gdańsk); EPA: China (Tsing Hua), Japan (Honshu: Lake Biwa-Ko; Hokkaido, Ryukyu Islands, Satsunan Islands), Siberia (rivers Ob: Tomsk, Amur, Chulym), Taiwan; ORR: Indonesia (Sumatra: Balige); AUS; NEA: USA (New York: Monroe County; Lake Ontario: Grandvue; Lake Michigan: Charlevoix; Pennsylvania); NEO: Argentina (Rio Negro: Puerto Blest, Charka Jockey; floodplain of Paraná river: Sta. Fé, El Tigre; Paraná river: island Los Sapos; Rio de la Plata: Atalaya); MED: Gulf of Lion (Golfe D Aigues-Mortes: Otoplana zone, Fize 1963, identity uncertain) (An Der Lan 1939, 1961, 1962, Ax 1957, Bauchhenss 1971, Beklemishev 1921, 1922, Braun 1885, Brusa 2006, Chodorowski 1959, Den Hartog 1977, Dorner 1902, Fuhrmann 1894, Fulinski & Szynal 1932, Gamo 1987, Gamo & Norena- Janssen 1998, Gieysztor 1926, 1939, von Graff 1911, 1913, Heitkamp 1979, Heitkamp et al. 1985, Hofsten 1907, 1911, Kaiser 1967, 1969, 1974, Kolasa 1979, 1983, Kolasa et al. 1987, Kosler 1962, Kraus 1965, Luther 1960, Mack-Firă 1968b, 1973, 1974, Meixner 1915, Müller & Faubel 1993, Nasonov 1924, Nasonov 1919a, b, 1925, Noreña 1995, Noreña et al Okugawa 1953, Papi 1952, Pörner 1966, Reisinger & Steinböck 1925, Rixen 1961, 1968, Schwank 1976, Seifert 1939, Sibiriakova 1929, Southern 1936, Steinböck 1933a, 1949, 1951a,b, Tu 1934, Valkanov 1926, Woodworth 1896, Young 1970, 1973, Zykoff 1902). Morphological notes (Plate IAa). Body length of solitary individuals up to 1.8mm, of asexually produced chains up to 8mm. Asexually produced chains could composed of a stock of up to 18 zooids. Anterior body-end conically pointed; posterior body-end tapering to a pointed end, sometimes tail like, provided with adhesive papillae (Reuter 1978). Sensory bristles, in particular, at extremities present. Body completely covered with cilia. At the border of the mouth microvilli form a carpet continuing into the body cilia. Cilia in the mouth shorter and less matted than those of the body; some of them with swollen tips. Globular bodies, 0.8µm in diameter, in the border area of the mouth (Reuter 1978). Colour variable from colourless to white or yellow, sometimes reddish, grey or brownish. Close to the foreend two reddish eyes and caudal from them characteristic ciliary sensory pits. Bauchhenss (1971) found eyeless specimens dominantly in the mud of rivulets and rivers. It seems to be a relationship between light intensity and development of pigments (Bauchhenss). Between eyes a frontal organ (Luther 1960) opens to the exterior (evidently, tracks of rhammite glands lying farther caudad, v. Graff 1913). Epidermis cellular with well developed extracellular matrix and connective tissue filaments being abundant in conspicuous extracellular spaces. If a basal lamina exists is uncertain (Pedersen 1983). Orthogonal nerve 42

43 system with brain, three pairs of nerve cords and pharyngeal ring system (further informations see chapter Nervous System). Protonephridia with bilateral stems and separate pores in the fore-body. Mouth in fore-end followed by an huge expansible pharynx simplex; mouth merges into pharynx without any clear borderline. Intestine ciliated with blind preoral gut. Predator; food: hydroids, turbellarians, nematods, rotifers, oligochaetes, Lynceidae (Conchostraca), Cladocera, copepods, ostracods, and chironomid larvae. Cnidocysts (nematocysts) of species of Hydrozoa on which M. lineare feeds, are intregated into the epithelium and peripheral parenchyma; these cnids are called cleptocnids. Most cnids are found subepidermally, included into large cells and enclosed by a membrane. The cells of the cysts contain generally one single nematocyst and do not show any sign of degeneration; its nuclei are unchanged and the cell plasma weakly stained and more liquid than usual. The walls of the cysts are strengthened proximally, often with a slight depression containing a cell with nucleus (Karling 1966). Reproductive system (Plate IAb,c) with bilateral testes and single ovary. Vasa deferentia pass into seminal vesicle in a common pore. The seminal prostatic vesicle distally surrounded by prostatic glands, enters directly into the proximal stylet. True prostatic vesicle absent. Stylet spiralled, corkscrew-like, 78µm in length (95µm after Meixner 1915, up to 200µm after v.graff 1913, µm after Bauchhenss 1971). Female system simple consisting of an ovar containing one to four follicles, ciliated female duct (oviduct) and ventral female pore. Each follicle of the ovar is composed of primarily 4 to 12 germ cells of which only one cell yields sexual maturity. The other germ cells perish. Only one mature oocyte passes into the proximally distensible oviduct which ventrally opens to the exterior anterior to the male pore. Female duct surrounded by glands with granulated interior. Gonopores separate. Development proterandrous. Remarks. Beklemishev (1950) described a species determined as M. lineare, from Khanka Lake, settlement Kamen Rybolov, area of Vladivostok, in the Far East of Russia. Specimens produced asexually chains of up to 12mm length by 1mm width, were of pink colour and eyeless. Reproductive system unknown. Eyeless specimens or specimens with great variations of eye-pigment (cf. Microstomum sp. Müller & Faubel), were reported by von Graff (1913), Meixner (1915), Luther (1960), Young 1970, and Müller & Faubel (1993). Meixner (1915) reported that specimens of M. lineare which live in the Moorlöcher des Lunzer Oberseemoores did not have integrated cnides in the epithelia because of absence of Hydrozoa in the swamp. Ecological notes. In the palearctic, M. lineare lives particularly in phytal regions of stagnant or slowly running waters; eurytopic and eurythermic, M. lineare belongs to the most abundant microturbellarians (Heitkamp 1982). Schwank (1980) reckoned M. lineare also to the character species of moderately polluted water-bodies. In Lake Constance, M. lineare was most abundant in the Cladophora-fringe of the rocky splash zone than in sandy or muddy areas, advantaged on the basis of the vegetative reproduction and the greater food supply in this area (Schwank 1976). M. lineare proved to be the greatest predator. After Karling (1974b), M. lineare, a lacustrine species, is one of the commonest species in the inner Baltic with a salinity tolerance of 6-8 and is able to descend to rather deep waters. In shore pools, M. lineare was not found (Karling 1974b). After Heitkamp (1982) and Bauchhenss (1971), M. lineare could be found from Februar to November/December. Maxima of abundance (Fig. 89) occurred between April and June and August and November ( ind./m², Heitkamp 1982). The species undergoes a polyvoltine life cycle producing up to 4 generations per year; eggs were produced from October to the end of the cycle (Heitkamp 1982). Bauchhenss (1971) found animals of M. lineare of different outline of body in one and the same pond. The differences are depending on environmental factors. The series range of the animals is considerable. The size of an animal depends on the reproduction period. In spring, the time of vegetative reproduction, 43

44 specimens are to find with slender and relatively short zooids. In late summer and fall, the time of the sexual reproduction period, only single animals or chains consisting of two huge zooids, are to find. Autecological characterisation (Kaiser 1969, Heitkamp 1979, 1982). Temperature, calcareus content, oxygen, and substrate: euryplastic; ph: mesoplastic; water current: oligo- to mesoplastic; flow conditions: meso- to polyplastic; phytophilous. Specimens collected by Young (1973) were found in lakes of England with a content of calcium varying between 1.7 mg/l and 50 mg/l. After Brusa (2006), the body length of chains runs up to 5mm depending on zooids developed. Colour yellowish white (? in i.l.). Anterior end with four brown pigmented epidermal spots. Cnidocysts present in some specimens. Specimens collected, were associated with floating vegetation. The environmental data at time of sampling (Febr. 2002) were running as follows: salinity 1.5, conductivity 438µS, total dissolved solids (TDS) 220mg/L, ph 7.03, O mg/L, T 16.7C. Food. M. lineare subsists zoophagously and saprophagously and predates on all specimens which could be overpowered (Heitkamp 1982): Hydroida (Hydra spp., Cordylophora ssp.), Turbellaria (Gieysztoria spp., Microdalyellia spp., Gyratrix hermaphroditus Ehrenberg), Rotifera, Nematoda, Oligochaeta, Copoda, Cladocera, Ostracoda, larvae of insects (Chironomida, Ceratopogonida, Ephemerida etc.). After Luther (1960) the main prey could consist of Hydra spp. Predators on M. lineare are Gastropoda (Lymnea stagnalis (L.), Planorbis corneus (L.), zoophagous oligochaetes (Chaetogaster diaphanus (Gruithuisen), Copepoda (Macrocyclops albidus (Jurine), Cyclops strenuus Fischer, etc.) newts and juvenile fishes (Heitkamp 1982). Parasites. Rixen (1961) observed in the gut of a specimen of Microstomum lineare a cysticercoid of a species of the genus Hymenolepis, Cestoda. That was the first evidence of a parasitic infection of a turbellarian species with a larva of the Cestoda. Westblad (1923, p , Fig. 6e) found in intestinal and parenchyma cells rounded bodies enclosed with thick membranes which are structured on its surface. After Luther (1904) these cysts are parasitic Protozoa (? Sporozoa). Microstomum bispiralis Stirewalt, 1937 (Plate II: C; Tab. 1) Type locality.: Pools in the vicinity of the University of Virginia, Virginia, USA, NEA; types: deposition not recorded. Habitat. Pools of freshwater. Morphological notes. Body length of asexually produced chains, 8 zooids as a maximum, up to 4.0mm. A chain is usually composed of four zooids, two well developed and each subdivided by a faint fission plane. From the level of the ciliary pits, the anterior body sets off an abruptly tapering, short cone; hind end blunt. Rhabdites absent. Adenal mucous glands irregularly distributed over entire body. Cerebral ganglia were found invariably well anterior to the preoral gut. Preoral gut extending anteriorly scarcely beyond the limits of the pharynx. Intestinal lining ciliated. Species protandrously hermaphroditic. Chromosome number n = 8. Reproductive system (Plate II: C) with bilateral testes and single ovary. One testis is developed earlier than the other one. Vasa deferentia join seminal prostatic vesicle. Seminal prostatic vesicle surrounded by a heavy muscular wall. Distally large, single-celled prostatic glands are arranged at the proximal base of the sytlet. Stylet (Plate II: Cb) sharply bent into two planes, making a smooth spiral. Its axis is 120µm long; stylet distally pointed with subterminal opening on the concave side. 44

45 Microstomum crildensis Faubel, 1984 (Plate I: B) Type locality. Crildumer Siel, Jade Busen, North Sea, ANE, leg. Mai 1980; holotype not deposited. Habitat. Eulittoral lentic lower mudflat, marine. Morphological notes (Plate I: B). Body length of sexually mature solitary specimen up to 0.9 mm, asexually produced chains with normally 3 zooids but 4 zooids present as a maximum, length of chain up to 1.5 mm. Body ends rounded, hind-end with adhesive papillae. At level of brain constriction dividing body from preoral head. In t.l. zooids transparent with darker contrasting intestine; solitary specimens dark grey. Eyes, rhabdites, and cleptocnides absent. Preoral gut insignificant. Gut filled with nauplii of harpacticoids. Reproductive system (Plate I: B) with single testis and ovary. Fields of spermatogonia in the posterior body-end. Ovary in front of male complex. Seminal prostatic vesicle present. Stylet (Fig. x) a bow-shaped tube, 32µm in length (d = 23.4µm) with distal opening terminal. Microstomum dermophthalmum Riedel, 1932 (Plate II: A) Type locality. Engelskmandshavn near Godhavn, Greenland, Davis Strait, ANW; types: deposition not recorded. Habitat. Sublittoral benthal, sand, mud, down to 15m water depth, marine. Geogr. distribution. ANE: North Sea (Iceland: Isafjörður), Skagerrak (Riedl 1956, Steinböck 1938). Morphological notes. Body length of asexually produced chains, up to 0.32mm. Anterior end conically pointed; posterior end tail-like pointed. Colourless. Ciliated pits behind marginal eyes. Body muscle wall structured as usual, heavily developed. Dorso-ventral muscle fibres faint. Two types of rhabdites mainly in the.anterior and posterior body-end; rhabdites of lateral glands are short, roundish to oval, gleaming yellowish, crowded to rods; rhabdites of median line spindle-shaped, in bundles of 4 to 5 rods.pharynx surrounded by pharyngeal glands at transition into intestine. Preoral gut extends anteriad to brain. Reproductive system (Plate II: A) with bilateral testes and single ovary. Testes located behind ovary. Vasa deferentia enter separately seminal prostatic vesicle which is surrounded by a strong muscle wall. Stylet (Plate II: Ab) straight tube with distal toothed thickening (recontruction after a serially sectioned specimen). Distal opening subterminal. Female gonopore in the middle of the second body-third. Gonopores separate. Microstomum gabriellae Marcus, 1950 (Plate II: F) Type locality. Island of São Sebastião, Bay of Santos, Brazil, ASW, leg. April, June, Nov. 1949; types: unknown. Habitat. Sublittoral fringe, phytal, among algae, chiefly Sargassum stenophyllum (Mertens), marine. Morphological notes (Plate II: Fa). Body length of chains up to 3.0 mm, fore-end of body pointed, with marginal red eyes (pigment spots), and ciliated pits at transverse level of mouth; rear body- end roundish with numerous adhesive glands. Epidermis with depressed nuclei in the ciliated pits and anterior region of body; epithelial nuclei in the remaining epidermis of body. Epithelial rhabdites and different adenal glands present. Frontal glands lie in front of the brain, which open in a frontal pore. Preoral gut present. Chaining specimens with up to 7 45

46 zooids. Cleptocnides faintly stained rods after Marcus (1950) - present (cf. Microstomum hamatum). Reproductive system (Plate II: Fb) proterandrous. Bilateral testes with distinct tunica propria lie in front of gonopore; the short vasa deferentia open from behind into the seminal prostatic vesicle in which the curved stylet is anchored distally. Single ovary present. Gonopores separate. Microstomum groenlandicum Levinsen, 1879 (Plate II: D) Type locality. Egedesminde, Disko Island, Greenland, Davis Strait, ANW; types: not prepared. Habitat. among Ulva sp., marine. Geogr. distribution. ANE: North-east Atlantic: Ireland (Co. Mayo: Blacksod Bay, Clare Island, Co. Galway: Mweeloon Bay, New Harbour), English Channel (Plymouth Sound), North Channel (Firth of Clyde: Millport), North Sea (Norway: Bergen) (Gamble 1893, von Graff 1905, 1913, Meixner 1938, Southern 1912, 1936). Morphological notes (Plate II: D). Body length 1.0 to 2.0mm composed of up to 8 zooids. From level of ciliary pits, the anterior body sets off an abruptly tapering, short cone; hind end tail-like provided with adhesive papillae. Brickred, oval eyespot above brain. Ciliated pits small, at level between mouth and brain. Bundles of rhabdites oval (24µm long, single rods up to 16µm long, specimens from Bergen, after von Graff 1905), well developed anteriorly, more sparsely in the posterior body; rhabdite rods spindle-shaped with one end more pointed than other one. Preoral gut extending anteriad to brain. Reproductive system (Plate II: D) with single ovary. Stylet slightly spirally contorted tube ending distally in a flattened spoon-shaped broadening. Drawing of the stylet absent. Remarks. There are several reports on M. groenlandicum but with the exception of Levinsen (1879), no one observed the genital organs. Therefore, the determinations made by Southern (1912, 1936) were only based on the brickred oval eyespot. Gamble (1893) placed his specimens here, for although it does not agree exactly with Levinsen s description (the red spot at the anterior end is wanting), it does agree with a form described by von Graff (1905) from Millport. Fig. 28. Microstomum hamatum. A-C. Cysts with cleptocnides in transversal section. D. everted desmoneme. E. cyst with rhabdite-like cnids. F. a. microbasic mastigophores, b. microbasic euryteles, c. desmoneme (after Karling 1966). Microstomum hamatum Westblad, 1953 (Plate I: H; Fig. 28) Type locality. Amphioxus sand between Oöy and Blomöy, Herdla, Norway, North Sea, ANE; leg. Karling, 1934; types: deposition not recorded. Habitat. Sublittoral benthal, mud, sand, Amphioxus sand, down to 40m water depth, marine. Geogr. distribution. ANE: North Sea (Norway: Mariholmen, Blomsterdalen: tidal zone off biological station Espegrend, Håkonsund), Skagerrak (Gullmarfjord: Kristineberg), English Channel (Plymouth Sound: harbour of Plymouth; Blyth: harbour) 46

47 (Karling 1966, Westblad 1953, 1955). Morphological notes (Plate I: H). Body length of asexually reproducing chains, evidently 2 zooids as a maximum, up to 2.0mm, narrow and thread-shaped, usually yellowish, especially the intestine, and with dark greyish pigment spots. Posterior body-end with adenal glandular papillae; anterior body-end with adenal gland cells as well. Bundles of rhabdites, rods about 16µm in length, sparsely dispersed over whole body surface. Globular formations (Fig. 28E), 12-15µm in diameter, containing 4-6µm long, almost unstained rods being different from the usual erythrophilous rhabdites, are abundant (cf. Marcus 1950, Plate VII: Figs 34, 48; Westblad 1953, p. 398). Different types of cleptocnides (Fig. 28) contain microbasic euryteles (Fig. 26Fb), microbasic mastigophores (Fig. 28Fa), and desmonemes (Fig. 28Fc). Cysts (Fig. 28E) are circular, 25µm in diameter and with central vacuole containing 5 10 cnids (Karling 1966). Sexual reproductive system with bilateral testes and single ovary. Number of testes could vary but depending on the state of development; if specimens have developed big testes only one of the testes seems to be well developed. Stylet funnel-shaped, 60-70µm in length, with distal hook-like bend (Fig. x). Gonopores seaparate. Remarks. The kind of rods enclosed in cysts in the epidermis (Fig. 26E) were also observed in Microstomum gabriellae Marcus, M. ulum Marcus, M. rubromaculatum von Graff, and M. mundum von Graff. Von Graff (1908, p. 2041) regards the rods as a simple, between rhammites and nematocysts placing type. Karling (1966) based on renewed studies, could demonstrate that all rods proved definitely to be true nematocysts. Microstomum jenseni Riedel, 1932 (Plate I: C; Figs 78, 85; Tabs 5, 10) Synonymy. Microstomum tortipenis Steinböck, 1938; p. 7, fig. 4 a-c. Type locality. Engelskmandshavn, near Godhavn, Disko Island, Davis Strait, ANW; leg. Steinböck 1926; types: deposition not recorded. Habitat. Eu- and sublittoral benthal, fine to coarse sands, down to 300m water depth, marine. Geogr. distribution. ANE: Celtic Sea (Scilly Islands: Tresco Island), North Atlantic (Iceland: Isafjörður), North Sea ( Island of Sylt, Norway: Grimseidpollen near Bergen), Skagerrak (Gullmarfjord) (Faubel 1974, 1977a, Faubel & Warwick 2005, Steinböck 1933b, Westblad 1953, 1954). Morphological notes (Plate I: C). Body length of asexually produced chain up to 0.6mm. Anterior body-end conically pointed, posterior body-end tail-like. Some specimens with light circular band at level of brain transverse to the longitudinal axis. Ciliary pits present. Bundles of rhabdites, 3 to 8 rods, evenly distributed over the body. In particular in the fore-end, there are large vesicles (rhammite glands?) containing long, red coloured rods being pointed on both sides (rhammites?) or pointed only on one side. In addition, there are lateral vesicles containing 15 to 20 green-yellow grains. Preoral gut extends anteriorly to brain. Intestinal lining interspersed with Minotian cells, scarcely ciliated but some parts non-ciliated; muscle wall of gut with strong longitudinal muscle fibres. Cleptocnides (nematocysts) dispersed in parenchyma and intestinal lining. Karling (1966) observed a kind of cyst consisting of one single parenchymal cell containing 1-3 oriented cnides; the cysts were rather common close to the basement membrane. Reproductive system (Plate I: C) with single testis and ovary but specimens with paired testes were observed. Seminal prostatic vesicle with distally arranged prostatic glands, joined with proximal base of stylet; its muscle wall three-layered with inner longitudinal, intermediate circular, and outer longitudinal fibres. Stylet, 80µm in length, obviously very 47

48 variable in its form: either straight or double S-haped in two planes. Distal tip with terminal aslant opening. Gonopores separate. M. jenseni developes protogynously. Remarks. Problematic or somewhat confusing seems to be the ascertainment made by Riedel that in some specimens the testis was either developed singly on the left or right body side or testes were developed bilaterally. It is not to exclude that there were two different species brought together, the more so as Steinböck who collected the specimens, presented drawings of divergent stylets (Riedel 1932, fig. 11). After the description of M. jenseni by Riedel (1932), furthermore records were given by Steinböck (1938) from Iceland described as M. tortipenis, by Westblad (1953) from the Scandinavian west coast, Gullmarfjord, and by Faubel (1974) from the island of Sylt, North Sea. The species M. tortipenis Steinböck is evidently synonymous to M. jenseni Riedel because the only differences lie only in large epithelial, bottle-shaped glands discharging probably a glutinous secretion for a very fast adhesion to surfaces (adhesive papillae?). That was not mentioned by Riedel, 1932, for her specimens. Another difference may be that M. tortipenis developed asexually chains of four zooids. Individuals described by Riedel and Westblad evidently reproduce asexually very infrequent. M. jenseni sensu Westblad displays essentially greater differences to M. jenseni Riedel. These are as following, viz. specimens living exclusively in the sublittoral in or on mud bottoms, length of body up to 1.4mm, epithelium with bundles of rhabdites of two sorts scattered over whole body, plenty of adhesive papillae only on caudal body-end, testis unpaired always localised dorsally, seminal vesicle with muscle fibres plaited in one another in different directions - not arranged in three layers, and stylet, 150µm long, debouching into the posterior part of the seminal vesicle, prostatic glands not observed. Female system developed as usual with ovary and oviduct. Gonopores separate. M. jenseni was recorded by Faubel (1974) from the eulittoral of semi-exposed sandy beaches of the island of Sylt (Figs 78, 85). Differences to the species described by Riedel (1932) and Westblad are as follws: constancy of a single testis located on the left body-side, absence of rhabdites, dominant asexual reproduction over the whole period of life, length of chains up to 2.0mm (usually composed of six zooids, two well developed and each subdivided by two faint fission planes), length of sexually mature solitary specimen up to 0.9mm, length of stylet 70µm, and outline of body with rounded extremities. In comparison of all these characters given in each the descriptions, the author is convinced that different species could ranked under the name Microstomum jenseni Riedel, Despite of the meagre description given by Steinböck (1938), M. tortipenis has to be reckoned synonymous with M. jenseni Riedel. M. jenseni sensu Westblad and M. jenseni sensu Faubel reveal characters which would justify the establishment of valid species each. However, the author prefers to desist from doing that because nothing is known on the potential variability of the specimens impacted by the different habitats the species were living. Microstomum karlingi nom. n. (Plate I: E) Synonymy. Microstomum papillosum von Graff, 1882 sensu Westblad 1953; p fig. 11. Type locality. Herdla, Kværnepoll current, Norway, ANE; leg. T.G. Karling; types: not prepared. Habitat. Sublittoral of algal belt, among Hydroids on Laminaria (at Herdla), marine. Geogr. distribution. ANE: Skagerrak (Gullmarfjord) (Westblad 1953). 48

49 Morphological notes (Plate I: Ea). Body length of asexually produced chains, up to 5 zooids, 1.5mm to 2.0mm, thread-like, white in i.l. Species lacks the broad frontal end. Frontal end provided with two characteristic bows of adhesive papillae, inside which there is a big rhabdite field. Reproductive system (Plate I: Eb). Male copulatory apparatus with bow-shaped stylet, about 60µm long, similar to the stylet of M. septentrionale, but narrower, and with its proximal part curved inwards. Remarks. Microstomum karlingi found by Karling and determined by Westblad (1953) as Microstomum papillosum von Graff, is clearly a new species. M. papillosum differs distinctly from M. karlingi through the absence of the two characteristic bows of adhesive papillae and the big rhabdite field at the frontal end, the development of the characteristic bend of the distal stylet, the different body-length and the number of zooids (cf. Faubel 1974). More similarities could be found between Microstomum septentrionale and M. karlingi, however, the stylet of M. karlingi is narrower and proximally curved inwards. Microstomum melanophthalmum Steinböck, 1933 (Plate II: J) Type locality. Isola S. Andrea, Rovinj, Croatia, Adriatic Sea, MED; types: deposition not recorded. Habitat. Sublittoral benthal between rocks, shells, and phytal within crops of Sphaerococcus coronopifolius Stackhouse, Halopteris scoparia (L.), Hypnea musciformis (Wulfen), Posidonia oceanica (L.), Peyssonelia squamaria (S.G. Gmelin), Dictyopteris membranacea (Stackhouse), Vidalia volubilis (L.), Halimeda tuna (Ellis & Sol.), and Udotea petiolata (Turra) down to 7m water depth, marine. Geogr. distribution. MED: Ligurian Sea (Porto Venere), Tyrrhenian Sea (Capo di Sorrento), Gulf of Lion (Banyuls sur mer), Sicily (Sampieri), Adriatic Sea (Croatia: Isola Sant'Andrea, Crveni Otok, Isola Rossa, Rovinj) (Riedl 1956, 1959, Steinböck 1933c). Morphological notes (supplemented by Riedl 1959). Body length of asexually produced chain, two zooids, probably shorter than 2.0mm; solitary specimen up to 0.7mm long, colourless with yellowish contrasting gut (Plate II: Ja). Posterior body-end somewhat pointed with adhesive glands, anterior end bluntly rounded. Eyes black to dark brown, crescentically enclosing distinct lense; eyes located near frontal end (Plate II: Jb). Ciliary pits present. Sexual reproductive system partly unknown. Male copulatory system with seminal vesicle and distal, 30µm long stylet (Plate II: Jc). Stylet proximally starting with flat funnel strongly decreasing distad in diameter; the middle part of the tube is bent almost at an angle of 90 from the main axis forming a hook. Distal end pointed with terminal opening. Microstomum papillosum von Graff, 1882 (Plate I: D; Figs 78, 88, 90; Tabs 3, 5, 10) Synonymy. Turbellarié de Sartor Oë» Claparède 1861 ; p. 152, pl. 5 : fig. 1.? Microstomum ornatum Uljanin, 1870; p. 42, pl. IV: figs 2-3. Type locality. Sartor Oë, Norway, leg. Claparède; types: deposition not recorded. Habitat. Sub- and eulittoral benthal, sandy beaches, marine. Geogr. distribution. ANE: Norwegian Sea (Iceland: Isafjörður; Norway: Tromsö), North Sea (Norway: Herdla; North Frisian Islands: Sylt), Skagerrak (Gullmarfjord: Blåbergsholmen); Baltic Sea (Kieler Bucht), Celtic Sea (Scilly Islands) MED: Gulf of Lion (France: Banyuls sur mer); Sicily (Sampieri; Adriatic Sea: Gulf of Trieste, Gulf of Venice: Rovinj; Tyrrhenian Sea (Gulf of Naples: Capo di Sorrento); Bosporus (Bebek, Baltaliman), Sea of Marmara (Florya, Pendik, Küçük, Su Island Heybeli), Black Sea (Crimea: Sevastopol, Turkey: Sile) (Armonies 1987, Ax 1959, Böhmig 1889, Faubel 1974, 1976, 1977a, Faubel & 49

50 Warwick 2005, Hellwig 1987, v. Graff 1913, Micoletzky 1910, Riedl 1956, Steinböck 1938, Wehrenberg & Reise 1985, Westblad 1953). Morphological notes (Plate I: D). Body length of sexually mature solitary specimen up to 0.9 mm, asexually produced chains with 4 zooids as a maximum, up to 1.5 mm. Body ends rounded, rim of hind-end with significant adhesive papillae; few papillae dispersed along lateral margin. Colourless, with intestine contrasting reddish brown. Eyes absent. Bundles of rhabdites (2 3 rods) and preoral gut present. Brain ventral of preoral gut. Epidermis with adenal nuclei and rhabdite glands. Basal membrane indistinct. Body muscle wall structured as usual; dorso-ventral muscle fibres dominantly developed in anterior body and lateral of intestine. Cleptocnides (nematocysts) present. Pharynx ciliated; extrapharyngeal glands debouch its secretion into the middle part of the pharynx. Intestine interspersed with Minotian cells, provided with long cilia decresing posteriad, and walled with circular muscle fibres. Gut filled with nauplii of harpacticoids. Reproductive system with single testis and ovary. Fields of spermatogonia caudal of ovary. Ovary at transition from second to last third of body. Seminal prostatic vesicle joind with stylet. Stylet of fully sexually mature solitary specimen widely bow-shaped, d = 80µm long; distal small, hook-like tip turned at an obtuse angle from the main plane into a second plane (Plate I: D). Antrum masculinum absent. Development protandrous. Remarks. Westblad (1953) did not exclude a synonymy of Microstomum papillosum with M. ornatum Uljanin and M. septentrionale Sabussow because all these species were characterised by a bow-shaped stylet but anyhow incompletely described. The stylet of M. ornatum was only described in the text but not figured by Uljanin. Therefore, M ornatum has to be transferred to the category species dubiae. M. papillosum and M. septentrionale are distinct valid species differing from each other by the outline of the stylets (cf. Faubel 1974 and Westblad 1953). Ecological notes. M. papillosum settles semi-exposed (Fig. 78) and lentic beaches and flats consisting of muddy, sandy mixed with mud, and sandy sediments (Dittmann & Reise 1985, Faubel 1976, Hellwig 1987). The population dynamic of specimens distributed on semiexposed beaches is given in Figs 88, 90. M. papillosum settled that habitat only in the first half of the year, from March to July. Dormancy prevailed from August to spring of the following year (Fig. 90) Maximal numbers of specimens were found from May to July, 7 to 14 individuals totally. After Hellwig (1987) most densities occurred in lentic muddy flats: up to 50 ind. in February (1982), averaged 25 ind./10cm², and up to 17,5 ind. in March (1983), averaged 6 ind./10cm². The life cycle of M. papillosum is presented in Fig. 90. The vegetative and sexual reproduction phase proceeds in spring. M. papillosum developes protandrously. More information see Ecological Account (Figs 78, 88, 90; Tabs 3, 5, 10). Microstomum septentrionale Sabussow, 1900 (Plate I: G) Synonymy.? Microstomum ornatum Uljanin, 1870; p. 42, pl. IV: figs 2-3. Microstomum ornatum Uljanin, 1870 sensu Sabussow 1897; p. 14. Type locality. Ljetnjaja Gubà, Solowetzk Islands, Barents Sea, AOE; types: not prepared. Habitat. Marine. Morphological notes (Plate I: G). Body length of asexually produced chains, two zooids as a maximum, up to 1.0mm, anterior end rounded, posterior end with blunt point. Adhesive papillae sparsely dispersed over body but intensively concentrated on the posterior body-end. Colour in i.l. yellowish with gut intensively yellow (specimens from Gullmarfjord often with orange yellow pigment at anterior rim of body, Westblad 1953, p. 402). Eyes absent. Bundles of rhabdites present. 50

51 Reproductive system with single testis and ovary. Fields of spermatogonia latero-frontal of female bursa. Muscle fibres attached to seminal vesicle obliquely extending to male gonopore. Male pore passes into spacious antrum masculinum. Numerous prostatic glands enter both antrum masculinum and seminal vesicle. Stylet strongly bow-shaped with length between 51-68µm (Plate I: G). Remarks. Confer remarks to Microstomum papillosum v. Graff, Microstomum spiculifer Faubel, 1974 (Plate I: F; Figs 11A, 78, 88, 90; Tabs 5, 10) Type locality. Litoralstation, List, Island of Sylt, North Frisian Islands, North Sea, ANE; types: deposition not reported. Habitat. Eulittoral semi-exposed sandy beach, marine. Geogr. distribution. ANE: North Sea (North Frisian Islands: Sylt) (Faubel 1977). Morphological notes (Plate I: F). Body length of sexually mature single specimen up to 1.0 mm, asexually produced chains with 4 zooids as a maximum up to 1.5 mm length. Body-ends rounded, hind-end with significant adhesive glands. Body colourless with gut contrasting reddish brown. Eyes absent. Cleptocnides (nematocysts) distributed over whole body. Less abundant than cnidocysts, in particular frontally, are bundles of rhabdites (each 2 3 rods). Epithelium with intra-epithelial nuclei. Body muscle wall with weak circular and strong inner longitudinal muscle fibres. Preoral gut extends anteriad above brain. Pharynx ciliated, distally surrounded by pharyngeal glands. Intestinal lining ciliated, looks syncytial and is extraordinary coarsely granulated; cilia of epithelial lining decreases posteriad. Gut filled with nematodes, harpacticods or nauplii from them. Reproductive system with single bilobed testis and ovary. Fields of spermatogonia caudal of ovary. Testis represents a bilobed sac at the right posterior end from which a short vas deferens between the bilobed parts passes into the seminal prostatic vesicle. The stylet (Plate I: F; Fig. 11A) almost straight, decreases from the proximal opening, a = 7-8mm, to a distal point. Distal opening terminal. The stylet projects into a distal antrum masculinum. Development protandrous. Ovary at transition of second to last third of body. Ecological notes. M. spiculifer settles semi-exposed beaches (Fig. 78) consisting of sandy beaches and sandy flats rich in detritus (Faubel 1976). The population dynamic of specimens distributed on semi-exposed beaches is given in Fig. 88. M. spiculifer settled that habitat only in the second half of the year, from August to December. Dormancy in that habitat prevailed from January to July of the following year. Maximal numbers of specimens were found in September and October, 12 and 11 individuals totally. The life cycle of M. spiculifer is presented in Fig. 90. The vegetative and sexual reproduction phase proceeds in fall. M. spiculifer developes protandrously. More information see Ecological Account (Figs 78, 88, 90; Tabs 5, 10). Microstomum trichotum Marcus, 1950 (Plate II: H) Type locality. Island of São Sebastião, Bay of Santos, Brazil, ASW, leg. June 1949; types: unknown. Habitat. Sublittoral fringe, phytal, among Corallinaceae, Jania rubens L., marine. Morphological notes (Plate II: H). Body length of chains with a maximum of 3 zooids up to 0.5 mm, fore-body conical resembling the proboscis of Alaurina alba, posterior end truncated; with almost invisible ciliated pits; at frontal margin a pair of unicellular knobs containing dark granules which look like eyes of Alaurina. The knobs are supplied with nerves. Adhesive papillae on the rear body-end present. Without eyes and tracks of 51

52 rhammites. Rhabdites united in thick, pyriform groups, 22µm long in sections. Nuclei of pharynx submersed. Nematocysts absent. Reproductive system with single compact testis. Male copulatory organ with bow-shaped, funnel-like stylet. (Plate II: H). Species incertae sedis aut dubiae: descriptions only based on juvenile specimens. Microstomum bioculatum Faubel, 1984 (Plate II: K; Tab. 5) Type locality. Off Keitum, Island of Sylt, North Sea, ANE; leg. Mai to June 1976 to 1979; holotype not deposited. Habitat. Eulittoral and superlittoral lentic upper mudflats and salt meadows, marine. Geogr. distribution. ANE: North Sea (Island of Sylt: Königshafen, off Kampen, north and south of Keitum; Jade Busen: Crildumer Siel) (Armonis 1987, Dittmann & Reise 1985, Faubel 1984, Hellwig 1987). Morphological notes (Plate II: K). Body length of asexually produced chains, 4 zooids as a maximum, up to 1.4 mm, terminally rounded, hind-end with long rigid cilia, in t.l. colour greenish yellow. Rhabdites scattered over body surface irregularly. Two lateral eyes composed of minute red pigment dots immediately at frontal margin. Adhesive glands at rear body-end, preoral gut, and ciliated sensory pits absent. Gut filled with diatoms. Chain of zooids see Plate II: K. Reproductive system unknown. Ecological notes. M. bioculatum settled the upper fluid layer of mud flats. It was observed (Faubel 1984) that specimens favoured to settle free tubes of small polychaetes. Maximum values of abundance, 121 ind./100cm², were found in the mud flat near Wilhelmshaven, Lower Saxonia (Faubel 1984). In semi-exposed detritus rich flats of the North Frisian Island Sylt, M. bioculatum was found from January to May, 1981, in low abundance (2.4 to 4 ind./10cm²). High abundance was recorded in April 1982, averaged 80.5 ind./10cm². The life cycle seems to be identical with Microstomum papillosum von Graff, The vegetative reproduction period could be followed from May to end of June. Solitary specimens becoming sexually mature, could not be observed from May to end of June in the time from 1976 to Dormancy prevailed from August to spring of the following year. Microstomum breviceps Marcus, 1951 (Plate II: G) Type locality. Island of São Sebastião, Bay of Santos, Brazil, ASW, leg. Nov. 1949; types: deposition not recorded. Habitat. Upper littoral, phytal, on algae, mainly Sargassum stenophyllum (Mertens), marine. Morphological notes (Plate II: G). Specimens with 3 zooids as a maximum; short precerebral region and spatulate caudal plate present; the latter with numerous adhesive glands. Precerebral region with rhammite glands, rhammite tracks and frontal glands. Ciliated pits small. Precerebral gut extends to the anterior border of brain. Rhammite glands with tracks extending anteriad to open frontally to the exterior. Eyes absent. Epidermis with depressed nuclei in the pre-cerebral area. Body muscle wall structured as usual but the muscle layers separated by a layer of parenchymatic cells. Pharynx with depressed nuclei and pharyngeal glands; divided by a fold in distal large pharyngeal lumen with long cilia and an proximal bilobate, narrow, pharyngeal lumen with short cilia. The distal one receives secretion of pink 52

53 glands, the inner part secretion of blue ones. Pharyngeal nerve ring present. Intestine nonciliated but provided with granular border; Minotian cells ( Körnerkolben ) present in the ventral pre-oral and post-oral gut. Reproductive system unknown. Microstomum canum Fuhrmann, 1894 (Plate III: C) Type locality. Augustinerholzbach, Basel, Switzerland, Europe; types: deposition not recorded. Habitat. Freshwater. Geogr. distribution. ANE: France (v. Graff 1913). Morphological notes (Plate III: C). Body length of asexually produced chains, 8 zooids as a maximum, up to 2.0mm. Eyes and cleptocnides absent. Anteriorly open numerous glands to the exterior. Ciliary pits behind brain at level of mouth. Posterior body-end tail-like. Pharynx and intestine ciliated like epidermis; pharynx entered by numerous glands. Preoral gut extends anterior to brain. Reproductive system unknown. Remarks. Hofsten (1912) and Meixner (1915) reckoned Microstomum canum a synonym of Microstomum lineare based on the great morphological variability of M. lineare, which was already mentioned by Braun (1885). Microstomum caerulescens (Schmarda, 1859) v. Graff 1882 Synonymy. Strongylostomum caerulescens Schmarda, 1859 ; p. 10, plate II, fig. 22. Typhlomicrostomum coerulescens: Diesing 1862; p. 235 Type locality. Freshwater lakes near Kingston, Jamaica, NEO. Habitat. Obviously in the phytal of freshwater pools and lakes. Morphological notes. Body length of asexually produced chains, two zooids, up to 0.67mm; anteriorly truncated, posteriorly rounded. Colour i.l. bluish. Pre-oral blind sac of gut extends close to anterior margin of body. Gut filled with decomposed yellowish brown detritus of plant material. Sexual reproductive system unknown. Microstomum caudatum Leidy, 1851 (Plate II: L; Fig. 94) Synonymy. Anotocelis caudata: Diesing 1862; p Type locality. Pennsylvania, USA, NEA; types: deposition not recorded. Habitat. Littoral, on Utricularia sp., floating Cladophora sp., freshwater. Geogr. distribution. NEA: USA (Lake Michigan: Charlevoix; New Jersey, Iowa: at Grinnell, Illinois: Mississippi Basin); EUROPE: Denmark, (von Graff 1913, Highley 1918, Kepner & Taliaferro 1912, Woodworth 1896). Morphological notes (Plate II: L). Body length of asexually produced chains, 8 zooids as a maximum but usually with three fission planes, up to 3.0mm. Anterior end rounded or terminating in a small, abrupt, rounded conical projection. Posterior end usually with prominent tail, distinctly elevated. Sexually mature specimens spindle-shaped with maximum body length of 1.5mm. Ciliated pits at level anterior to mouth opening. Mouth about one sixth of the body length posterior to anterior end. Colour very transparent, almost iridescent, pale, yellowish green; intestine when empty showing hardly any yellow at all, blending with surrounding parenchyma. Eyes absent. Cleptocnides (nematocysts) scattered evenly over the 53

54 body. Preoral gut, broad and obtuse, extend anteriad half-way between brain and anterior body-end. Ciliated pits, dorsal to mid-lateral surface of the body, a little anterior to the mouth. These organs together with the mouth can be closed or distended; the ciliated pit when closed, looks like a club-shape sac. The cilia are much stronger developed than cilia of the general surface. The ventral columnar cells are in intimate contact with the dorso-lateral nerve. The cells of the fundus of the pit, being pear-shaped and 10 to 12µm in diameter, are of glandular nature and are lying deeply embedded in the parenchyma; each cell has a glandular duct leading into the lumen of the ciliated pit. Brain, longitudinal nerve cords, pharyngeal nerve ring, and excretory system identical with Microstomum lineare. Cerebral ganglia connected by a very short, wide, transverse commissure, lie under the preoral gut. Pharynx with a sensory epithelium in the mid-ventral floor which is free from glandular ducts. The sensory floor stands directly in contact with the pharyngeal nerve ring. The manner in which the pharynx behaves in testing food suggests that this is an elementary gustatory epithelium (Kepner & Taliaferro 1912). Reproductive system. Sexually mature specimens were found only in female condition with a single ovary lying by the left side of the gut. Males are unknown. After Kepner & Taliaferro (1912) sexually mature specimens are not hermaphroditic. Microstomum davenporti von Graff, 1911 (Plate II: M) Type locality. Eelpond, Breakwater at Woods Hole, Massachusetts, USA, ANW; types: deposition not recorded. Habitat. Sublittoral phytal, Ulva sp., Sargassum sp., marine. Geogr. distribution. ANW: USA (Connecticut: Stamford, Massachusetts: cape Cod, Woods Hole) (Bush 1964, von Graff 1913). Morphological notes (Plate II: M). Body length of asexually produced chains, 4 zooids as a maximum, up to 1.5mm, colour whitish with intestine contrasting light-ochre. Posterior bodyend with adhesive plate separated by a distinct contriction from the anterior body. Adhesive papillae up to 12µm long. Rhabdites up to 12µm long, intensively concentrated on preoral head. Rhammite glands located lateral of pharynx, the tracks of which extend anteriad. Eyes absent. Ciliated pits present. Sexual reproductive system unknown. Microstomum deltanensis El Said, 1982 Type locality. Nile Delta area, Egypt, NAF; types unknown. Habitat. Freshwater. Remarks. The species was described in the M. Sc. Thesis from El Said (1982) at the Zagazig University, Egypt. There was no possibility to have direct access to that thesis. Microstomum lucidum Fuhrmann, 1896 Type locality. Baie de la Forest, Bay of Concarneau, Bretagne, English Channel, ANE; leg. autumn 1896; types: unknown. Habitat. Sublittoral benthal, marine. Geogr. distribution. ANE: North Atlantic (Faeroes: Vaagfjord, Suderø), English Channel (France: Bretagne) (Meixner 1938, Steinböck 1931). Morphological notes. Body length of asexually produced chains, 4 zooids as a maximum, up to 1.5mm, extremities bluntly rounded, colourless, transparent, intestine yellowish. Hind 54

55 end provided with adhesive papillae. Rhabdites with rounded ends distributed in bundles over the whole body surface. Eyes absent. Ciliary pits weak. Preoral gut present. Sexual reproductive system unknown. Microstomum mortenseni Riedel, 1932 (Plate II: B) Type locality. Disco Bay, Greenland, Davis Strait, ANW; leg. Steinböck 1926; types: deposition not recorded. Habitat. Sublittoral benthal, mud, down to 300m water depth, marine. Morphological notes. Body length up to 1.2mm, colour red. Epithelium with intraepithelial nuclei; basal membrane absent. Body muscle wall with stronger circular muscle fibres than longitudinal ones. Body muscles weakly developed. Head with rhammite glands tinged yellow; rods double-sided pointed. Lateral parts of body with bundles of rhabdites. Preoral gut extends far beyond brain to anterior body-end. Intestine evidently non-ciliated; muscle wall hardly to observe. Reproductive system incompletely known. Oogonia of ovary scattered mostly single or in groups of two or three within the parenchyma of the second body-half. Female gonopore in the middle of the second body-third. Male system incompletely known. Stylet S-shaped (Plate II: B). Remarks. Already Riedel (1932, p. 68) claimed the establishment of a new genus for M. mortenseni based on the diffuse, dislodged arrangement of the oogonia instead of the compact ovary typically present in the genus. However, because of the incomplete development of the male system the author desist from doing. Microstomum mundum von Graff, 1905 (Plate III: E) Type locality. Bay of Sevastopol, Crimea, Ukraine, Black Sea, MED; types: deposition not recorded. Habitat. Benthal, sand, marine. Morphological notes (Plate III: E). Body length of asexually produced chains, up to 8 zooids as a maximum, 2.0mm, colourless; posterior body-end provided with 20µm long tongue-shaped adhesive glands; some dispersed laterally anteriad. Eyes absent. Bundles of rhabdites, rods 16 20µm long, distributed over body; rods terminally pointed. Small, oval rods in the epidermis correspond to cleptocnides (cf. Microstomum hamatum) Preoral gut present. Intestine with characteristic lateral bulges, also present in preoral gut. Sexual reproductive system unknown. Microstomum ornatum Uljanin, 1870 Type locality. Bay of Kilenbalka, Black Sea, MED; types: not prepared. Habitat. Sublittoral, phytal on Zostera, marine. Geogr. distribution. MED: Adriatic Sea (Gulf of Trieste, Rovigno) (Micoletzky 1910, Steinböck 1933c)). Morphological notes. Body length not presented, extremities of body rounded, hind end with 6 or more adhesice papillae (after Uljanin, 1970, protuberances of epidermis). Colour of body transparent with intestine contrasting dark yellow. Bundles of rhabdites only on anterior body at level of constrictions (ciliary pits). Sexual reproductive system with single testis and ovary. Male apparatus with weakly bowshaped stylet. Ovary located in the hindmost part of the body. The ovary opens via the oviduct 55

56 to the exterior at the rear body-end. The development of oogonia seems to take place from behind anteriad. Remarks. Westblad (1953) reported with respect to Fig. 3 made by Uljanin (1870), it seems to me particularly absurd, according to which the ovary is situated in the hindmost part of the body, and the development of the egg seems to take place forwards instead of the contrary. Microstomum parádii v.graff, 1913 Synonyms. Derostoma squalus Duges, 1828; p. 142, plate 4, figs 5, 25, 26. Turbella squalus: Diesing 1850; p. 224 Type locality. Klausenburg, Transylvania, Romania, EUROPE. Geogr. distribution. EUROPE: France (Montpellier, Languedoc-Roussillon) (v. Graff 1913, Steinböck 1933c). Morphological notes. Length of body up to 2.5mm, anteriorly rounded, posteriorly shovel shaped, occupied with adhesive glands. Colourless. Epidermis with immotile but flexible spines. Rhabdites in packets, up to 8 in number, rhabdite rod only at one end pointed, the other end blunt. Eyes black with coned lenses. Gut light brown. Remarks. After von Graff (1913), Dugès (1828) drawings of Microstomum squalus allude rather to Microstomum lineare based on the outline and size (up to 3.3mm length), than to M. parádii. Microstomum philadelphicum Leidy, 1852 Type locality. Philadelphia, Pennsylvania, USA, NEA; types: not prepared. Habitat. Freshwater. Morphological notes. Body length of asexually produced chains, up to 4 zooids, 1.0mm, anterior body-end conical, posterior body-end rounded, colourless. Eyes absent. Preoral gut present. Sexual reproductive system unknown. Microstomum punctatum Dorner, 1902 (Plate III: D) Type locality. Pond near Linkenen, RU-KGD, Europe; types: not prepared. Habitat. Sublittoral, phytal, swampy, stygofauna, well, freshwater. Geogr. distribution. EUROPE: Germany (Saxonia: well in Steinbach, Thuringia: Lutterquelle) (Kaiser 1974, Wegelin 1966). Morphological notes (Plate III: D). Body length of solitary individuals about 1.0mm by 0.16mm width. Chaining individuals with 4 zooids as a maximum. Anterior end cuneiformly pointed and provided with tufts of sensory cilia. Colour brownish yellow (in t.l.). Hind end with pointed tail. Anterior end with characteristic black dotting. Eyes and cleptocnides absent. Ciliated pits at level of mouth opening; cilia of pits longer than epidermal ones; at the fundus of the pit cilia covered with glandular mucus produced by oblong cellular glands (cf. M. caudatum). Preoral gut short, not outreaching the mouth opening. Intestine with circular muscle fibres. Sexual reproductive system. Chaining specimens with single ovary being in different phase of development. Male apparatus unknown. Remarks. Kaiser (1974) reported the dicovery of M. punctatum at Lutterquelle (Thuringia) though he did not found specimens being sexually mature. The determination was only based on the habitus of the description made by Dorner (1902). The pointed anterior end counted to 56

57 5-6 adhesive papillae and the pregut extended only up to the limit of the mouth-slit. Cleptocnides present. In the specimens of Dorner cleptocnides absent. Microstomum rhabdotum Marcus, 1951 (Plate II: N) Type locality. Island of São Sebastião, Bay of Santos, Brazil, ASW, leg. Nov. 1949; types: deposition not reported. Habitat. upper littoral, phytal, on algae, mainly Sargassum stenophyllum (Mertens), marine. Morphological notes (Plate II: N). Specimens with 3 zooids as a maximum; body length of fixed specimens up to 0.7 mm by maximum width of 0.085mm; terminal ends of body rounded. Ventro-caudal and rostral body-ends provided with adhesive papillae. Characteristic arrangement of stripes of rhabdite-bundles on the dorsolateral sides, joined with each other at level of ciliary pits; cells of adenal bundles of rhabdites being bulbiform, contain about 20 rods that stain deeply with eosine. Median dorsal area and ventral side free of rhabdites. Cerebral glands stain erythrophilous. Epidermis with depressed nuclei in the pre-cerebral area and small adenal glands tinged cyanophilous. Body muscle wall structured as usual, not separated by parenchyma. Two kinds of pharyngeal glands enter pharynx in the area of the fold. Preoral gut extends at level of brain. Pharynx simplex with depressed nuclei and divided into 2 compartments by a fold; intestine ciliated. Sexual reproductive system unknown. Microstomum rubromaculatum von Graff, 1882 (Plate I: I) Type locality. Gulf of Naples, Tyrrhenian Sea, MED; types: deposition not recorded. Habitat. Sublittoral phytal and benthal, distributed in crops of Sargassum spp., on shells and sand, marine. Geogr. distribution. ANE: English Channel (France: Concarneau; England: Wembury) East Atlantic (Ireland: Co. Galway, New Harbour, Co. Dublin, Malahide Inlet), Northeast Atlantic (Iceland: Isafjörður, Faroes: Vaagfjord), North Sea (Norway: Herdla, Kvaernpol current,), Skagerrak (Gullmarfjord: Gåsövik, Fiskebäckskil) (Meixner 1938, Southern 1936, Steinböck 1931, 1938, Westblad 1953). Morphological notes (Plate I: I). Body length of asexually produced chains, 8 zooids as a maximum, up to 2mm. Anterior end broadly rounded with characteristic red pigment extending caudad to level of ciliary pits. Posterior end of the mostly two well developed zooids truncated, the rims of which provided with adhesive papillae. Rhabdites absent. Small, oval rods in the epidermis correspond to cleptocnides (cf. Microstomum hamatum). Small processes along lateral margin resembling papillae, consist only of rhabdites (Westblad 1953). Colourless, transparent, with gut contrasting brown. Preoral gut extends forwards anterior to brain. Sexual reproductive system unknown. Microstomum sp. Doe, 1982 (Fig. 17 B) Type locality. At pier of Marine Science Institute of the University of North Carolina, Morehead City, North Carolina, USA, ANW; types: not taken. Habitat. Sublittoral benthal, marine. 57

58 Morphological notes. The description of Microstomum sp. is only based on ultrastructural investigations of the male copulatory apparatus (Fig. 17B), i.e. stylet and seminal-prostatic vesicle. The cylindrical stylet tapers from proximal end, a = 7µm, to 4µm diameter just before the curvature begins; after the curvature the stylet tapers distally to a point with the opening occurring subterminally and laterally. Length d of stylet approximately 38µm, taken from Fig. 9 in Doe (1982). Proximally the stylet is connected to the seminal-prostatic vesicle by only a thin cytoplasmatic bridge (Doe 1982). The cytoplasmatic bridge acts as conduit for the passage of sperm, prostatic gland material and sensory structures from the vesicle to the stylet. Fig. 29. Microstomum sp. Kawamura. Chain of zooids (after Kawamura 1918). Microstomum sp. Gray & Rieger, 1971 Type locality. Stoupe Beck, Robin Hoods Bay,Yorkshire, England, North Sea, ANE; types: deposition not recorded. Habitat. Eulittoral benthal of an exposed sandy beach, grain size: M z φ between 1.89 and 1.96 and σi (sorting) between 0.54 and 0.55 (grain size determination after Folk 1968), marine. Microstomum sp.kawamura, 1918 (Fig. 29) Type locality. Lake Biwa-ko, Japan, ANW, EPA; types: not taken. Habitat. Sublittoral, ponds and marshes, freshwater. Morphological notes. Specimens with length-wise mouth located near anterior part of body on the ventral surface (Fig. 29). Eyes present. Excretory organ with single main duct. Ciliary sensory pits present. Sometimes, many cleptocnides were found. Intestine with preoral blind sac dorsal of pharynx. Reproductive system unknown. Ecological notes. Long chained populations were common in summer (Kawamura 1918). Microstomum sp. (cf. lineare (Müller, 1773) Müller & Faubel, 1993 (Fig. 30 A-D, Plate II: E) Localities. Stream-km 584, weir at Geesthacht, stream-km 592, stream-km 596 at Krauel, River Elbe, Germany, Europe; leg. D. Müller, July 1991; types: not prepared. Habitat. Eulittoral benthal, sandy or muddy sediments covered with algae or not, freshwater. Geogr. distribution. EPA: Japan (Lake Biwa-ko, Honshu) leg. Prof. Dr. O.A. Timoshkin, July Morphological notes. Microstomum sp. collected in the Elbe river (Fig. 30A), resembled Microstomum lineare (Müller) the exception being two dorsal and ventral black stripes of pigment parallel near the anterior margin. Other specimens cf. M. lineare (Müller) were found by Prof. Dr. Timoshkin in Lake Biwa, Japan, (Fig. 30B-D) with two dorsal and ventral darkbrown concentrations of pigment converging to the most rostral body-end (Fig. 30B-D). Marginal eyes-spots absent (cf. remarks to Microstomum lineare). Sexual reproductive system unknown. 58

59 Ecological notes. At site stream-km 592 of Elbe river, Microstomum sp. settled in an abundance of 112 ind./100cm². At the same time M. lineare (Müller) was sympatric but not sexually mature. Fig. 30. Microstomum sp. A. Drawing of Microstomum sp. Müller & Faubel, dorsal view. B. D. Microstomum sp. Microphotograph of slightly squashed specimen from Lake Biwa, in dorsal view (taken by Prof. Dr. O.A. Timoshkin 1997). D. Converging dark-brown pigment stripes to the most rostral end. Microstomum sp. Pereyaslawzewa, 1893 (Plate III: B) Type locality. Bay of Sevastopol, Crimea, Black Sea, MED; types: not prepared. Habitat. Marine. Morphological notes (Plate III: B). Body of asexually produced chain, 4 zooids, slender, colourless, with bluntly rounded body-ends. Eyes, rhabdites, and adhesive papillae absent. Ciliary pits somewhat anterior to mouth. Preoral gut extending anteriad, ends above brain. Reproductive system unknown. Microstomum sp. Rixen, 1961 Type locality. Westensee, Schleswig Holstein, Germany, Europe; leg. Rixen, May to Aug. 1957/58; types: not prepared. Habitat. Phytal, benthal mud, freshwater. Geogr. distribution. EUROPE: Germany (Schleswig Holstein: spring of Kellersee, canal of Eider near Projensdorf, Postsee, pool of Botanic Garden in Kiel) (Rixen 1961). Morphological notes. Small size of body, eyeless. Predation on rotifers. Reproductive system unknown. Ecological notes. Specimens were exclusively observed in pools where Microstomum lineare was absent. Microstomum sp. Schmidt, 1972 (Plate III: A) Type locality. South Grindöy, Tromsø-Sound, Norway, Norwegian Sea, ANE; leg. May 1971; types: not prepared. Habitat. Shallow sublittoral benthal, coarse sand mixed with fragments of mollusc shells, Md = mm, marine. Morphological notes (Plate III: A). Body length of chains up to 0.9mm by 0.1mm width. Two well developed zooids already starting chaining concurrently. In t.l. body colourless or 59

60 slightly light-brown with gut contrasting brownish to red-brown; in i.l. body colourless with gut taking on light brown colouration. Anterior body-end conically pointed, densely bordered with rhabdites which are exceeded by sensory bristles; along lateral margins bristles widely spaced irregularly. At the rear body-end, bristles in very dense accumulation with length of up to 20µm. Adhesive papillae, 3-4µm in length, present along lateral margins but they are immensely accumulated, 30 to 40 adhesive papillae, at the posterior rim of the second zooid; at the rear end of the anterior zooid, adhesive glands far less accumulated. Eyes absent. Peripheral parenchyma provided with glands, which are more abundant in the anterior body than in the posterior one; in the anterior zooid, glands also encompass the pharynx. Digestive tract with anterior blind sac. Reproductive system unknown. Ecological notes. After Schmidt (1972a) individuals swim very actively in the water column and they are also able to move very fast on the bottom. Besides they can move leech-like and then the creeping resembles that of gastrotrichs. Microstomum sp. Steinböck, 1948 Locality. Mouth of Mývatn, Laxá near Smiðjutjörn; Geldingaey, east of the bridge; Laugarvatn; Iceland, EUROPE; types: not prepared. Habitat. Freshwater. Morphological. Eyeless specimens without any characteristic morphological features. Chains of zooids sexually immature. Microstomum sp. Tyler, 1976 Localities. South shore, 1.5 miles from inlet, New River, North Carolina, USA, ANW; types unknown. Habitat. Sublittoral fringe, benthal, medium to fine sand, marine. Morphological notes were only given to the ultrastructure of the adhesive organ. Microstomum ulum Marcus, 1950 (Plate II: I) Type locality. Island of São Sebastião, Bay of Santos, Brazil, ASW; types: deposition not recorded. Habitat. Shallow sublittoral, benthal, coarse sand with single tufts of Padina sp. and other algae, marine. Morphological notes (Plate II: I). Body length of chains with a maximum of 4 zooids up to 1.1 mm, frontal body-end conical with well developed ciliated pits, posterior body-end developed as roundish plate with adhesive function. Eyes absent. Epidermis with intraepithelial nuclei and adenal rhabdites, 50 of which bundled per cell (25µm in diameter), similar to those of M. trichotum. Other voluminous cells of epidermis present with thick, faintly stained rods (cf. M. gabriellae, M. hamatum); nematocysts occur scarcely, always lodged in latter cells. Frontal glands open in a single pore to the exterior. Preoral gut short. Food Hydrozoa and Copepoda. Characteristic accompanying fauna Gyratrix hermaphroditus Ehrenberg and Dolichomacrostomum mortenseni Marcus. Sexual reproductive system unknown. Microstomum variabile Leidy, 1852 Synonymy. Anotocelis variabilis: Diesing 1862; p Type locality. Philadelphia, Pennsylvania, USA, NEA; types: not prepared. Habitat. Freshwater. 60

61 Geogr. distribution. NEA: USA (Lake Michigan: Charlevoix). Morphological notes. Length of asexually produced chains, 4 zooids, up to 1.0mm, extremities rounded, colourless. Eyes absent. Preoral gut present. Reproductive system unknown. Fig. 31. Myozonella microstomoides. Dorsal view of squashed specimen (modified after Beklemishev 1955). Myozonella Beklemishev 1955 Diagnosis. Microstomidae with pre-oral blind sac of gut. Ciliated sensory pits near front of body. Asexually produced discrete zooids (chains). Muscle ring on gut. Sexual organs and reproduction unknown. Freshwater. Type of the genus: Myozonella microstomoides Beklemishev, 1955 Myozonella microstomoides Beklemishev, 1955 (Fig. 31) Type locality. Village Sudimir, close to Bryansk, RU- C; leg. V.N. Beklemishev, 12. June 1915; types: unknown. Habitat. Phytal of small rivulets of swampy grassland in clear water, Utricularia sp., Calopteryx sp., with rich accessory fauna, freshwater. Morphological notes. Body length of asexually produced chain consisting of two zooids, up to 1.0mm (Fig. 31). Anterior end pointed, posterior end tail-shaped. Adhesive glands absent. Body transparent, with intestine taking on brownish colouration when food ingested. Eyes and rhabdites absent. Ciliated sensitive pits dorsal, opening via small long duct. Excretory organs bilateral. Pharynx simplex, ciliated, longitudinal muscles strongly developed, passes into gut; muscle ring on gut close behind pharynx. Sexual reproductive system unknown. Faunistic notes. Beklemishev (1955) stated a rich accessory fauna; dominant Turbellaria were recorded as follows: Microstomum lineare Oersted, 1843, Stenostomum leucops (Dugès, 1828), Castrella truncata (Müller, 1777). Genus Alaurina Busch, 1851 Diagnosis. Microstomidae with anterior proboscis provided with tactile bristles and papillae. Type of the genus: Alaurina prolifera Busch, 1851 Key to the species of Alaurina. 1 species without evenly spaced bristles around body 2 - species with evenly spaced bristles around body Alaurina prolifera 2 eyes at base of proboscis present Alaurina composita - eyes at base of proboscis absent Alaurina alba 61

62 Alaurina prolifera Busch, 1851 (Plate III: I) Type locality. Skye Islands, Inner Hebrides, Northeast Atlantic, ANE; types: unknown. Habitat. pelagic, marine. Geogr. distribution. MED: Spain (off Malaga); ANW: USA (off Newport, New England) (v. Graff 1913). Morphological notes (Plate III: I). Body length of asexually produced chain of two zooids up to 2.2mm. Anterior end non-ciliated and modified to form a tactile proboscis with numerous circular folds. Base of proboscis marked off by a tuft of cilia on each side. Bristles ingrained into a small epidermal papilla, evenly spaced along lateral margin; bristles double as long as body-cilia; longer single bristle at rear body-end, not ingrained into an epidermal papilla. Preoral gut present. Close behind mouth two lateral eyes. From ventral mouth eight strong muscular re- and protractors ( Binden after Busch 1951) extend to the epithelial muscle wall of the gut. Reproductive system unknown. Alaurina alba Attems, 1896 (Plate III: G) Type locality. Helgoland, North Sea, ANE; types: not prepared. Habitat. Pelagial, phytal, marine. Geogr. distribution. ANE: Kattegat (Danmark: Frederikshavn, Trindelen); MED: Gulf of Lion (off Banyuls sur Mer) (Brinkmann 1905, von Graff 1913). Morphological notes (Plate III: G,a,b). Body length of solitary specimens up to 1.6mm, of asexually produced chains with three to four zooids up to 2.5mm. Anterior body bluntly, conically pointed, non-ciliated, provided with single or manifold ring of cylindrical papillae; anterior to the ring of papillae, bundles of rhabdites and longer rigid cilia dispersed. Bundles of rhabdites also dispersed over the whole body surface. Adhesive papillae crowded around posterior body-end but sparsely spaced along margin of second body-half. Body colourless, with intestine contrasting yellowish due to ingested algae. Preoral gut present. Ciliary pits somewhat behind mouth. Eyes absent. Excretory system with lateral stems joined posteriorly in a single median vesicle; external pores of the lateral stems not observed. Reproductive system (Plate III: Gc) with single testis and ovary. Male system with seminal vesicle joined distally with bow-shaped, semi-circle stylet (Plate III: Gd). Stylet projects into antrum masculinum. After Brinkmann (1905, p. 61, Fig. 4) Kornsekretet ligger ordnet rosetformet I pølseagtige Klumper ved Overgangen (prostatic vesicle) til penis. Evidently, a true prostatic vesicle separated from seminal vesicle, present. Female duct short, proximally giving way to ovary. Gonopores separate. Alaurina composita Metschnikov, 1865 (Plate III: H) Synonymy: Turbellarié des Hebrides Claparède 1861 ; p. 151, pl. V : fig. 2. Alauretta viridirostrum Mereschkovsky, 1879; p. 35, pl.iv: fig. 1. Alaurina viridorostrum: v, Graff 1882; p Alaurina claparedei von Graff, 1882 ; p Dinophilus simplex Verrill, 1892; p. 458, pl. 2 : figs 6, 6a. Type locality. Coast of Skye-Hebrides, northeast Atlantic, ANE; types: not prepared. Habitat. Pelagial, marine. 62

63 Geogr. distribution. ANE: White Sea (Sea around Solovetzk Islands), North Sea (Sea around Helgoland, Den Helder, IJsselmeer), Kattegat (Danish water-bodies); Sea of Hebrides (Island of Skye), ANW: USA (Rhode Island: off Newport) (Brinkmann 1905, Gamble 1893, von Graff 1913, Hofker 1930). Morphological notes (Plate III: H,a). Body length of solitary specimens up to 0.9mm, of chains of asexually producing specimens, ten zooids as a maximum but usually 4 zooids, up to 3.0mm. Anterior end, proboscis-like, finger-shaped, non-ciliated, and provided with numerous circular folds occupied with rod-like papillae. At the tip of the proboscis open ducts of rhabdites (? rhammite tracks) glands to the exterior, located at level of brain. Base of proboscis marked off transversely by a tuft of cilia on each side. Posterior body-end tail-like with terminal tuft of rigid cilia. Colour of body light yellow, proboscis greenish yellow. Posterior to proboscis black eye-spots. Mouth ventral just behind base of proboscis. Pharynx provided with two kinds of pharyngeal glands. Intestine non-ciliated. Preoral gut extends anterior to brain. Food consists mainly of diatoms (Coscinodiscus biconicus Van Breemen) and Ciliata (Tintinnopsis fimbriata). Reproductive system with single testis bilobed. Stylet, short, slightly bow-shaped (Plate III: Hb) joined proximally to muscular seminal prostatic vesicle. Seminal prostatic vesicle lined with flat epithelium; sperm collects proximo-peripherally and prostatic glandular material accumulated centrally and at base of stylet. Female system unknown. Ecological notes. After Hofker (1930), Alaurina composita is an endemic species of the Zuidersee from which the North Sea population recruits every year (see Hofker 1930, p ). Genus Einarmicrostomum gen. n. Diagnosis. Macrostomida with pre-oral blind sac of gut. Asexually produced discrete zooids (chains). Male copulatory complex with tubular stylet; male canal extends behind male pore to enter pore from posterior. Female system with vagina and vaginal duct with separate openings. Ciliated sensory pits about at level of brain; frontal glands below brain present. Marine habitat. Type of the genus. Microstomum spiriferum Westbald, 1953 Etymology. The generic prefix Einar is dedicated to the famous turbellariologists Dr. Einar Westblad, Einarmicrostomum spiriferum (Westbald, 1953) comb. n. (Plate III: F, S1-4) Synonymy. Microstomum spiriferum Westbald, 1953; p , fig. 4. Type locality. Gullmarfjord, Sweden, Skagerrak, ANE; types: deposition not recorded. Habitat. Sublittoral benthal, mud, down to 60m water depth, marine. Geogr. Distribution. ANE: Skagerrak (Sweden: Bro Fjord, Färle Fjord; Norway: Oslo Fjord, Dröbak; Ramfjord: Tromsö), North Channel (Scotland: Firth of Clyde, Millport, Little Cumbrae Island) (Westblad 1953). Morphological notes (Plate III: Fa,b). Body length of asexually produced chains, two zooids as a maximum, up to 1.5mm; the proximal zooid sometimes subdivided by a faint fission plane. Colour pale reddish yellow owing to richly pigment spots in the dorsal surface. Ciliated pits form conspicuously reddish eye-spots running into each other dorsally. Bundles of rhabdites, 25-30µm in length. Cleptocnides (nematocysts), particularly, in anterior and 63

64 posterior body-end, in gastrodermis, parenchym and epidermis, dorsally and ventrally, mostly naked. Some thin-walled cysts contain 1-3 cnids and one cellular nucleus were found under the basement membrane (Karling 1966). Karling stated that the position of the thin-walled cysts at a distance from the epidermis suggests a parenchymal not epidermal origin of the cnid-containing cells. Adhesive papillae absent. Animals display a great vivacity with an even gliding movement on muddy bottoms. Reproductive system with single testis and ovary. Female system with two female ducts: vagina (anterior duct) and vaginal duct (posterior duct); both ducts connected with the ovary. Vagina and vaginal duct open separately to the exterior. After Westblad (1953) the anterior duct being ciliated, corresponds to the vagina obviously discharging the fecundated oocyte. The proximal part consists of a ciliated female atrium which is separated from the oviduct by a sphincter. The vaginal duct (posterior duct) serves as copulatory organ because its proximal part contains sperm while the outer part is shut and, obviously, opens only at copulation. The male system is composed of the seminal vesicle and the stylet which is often directed dorsoventrad. The muscular seminal vesicle is fairly small but the stylet is conspicuously large, 140µm in length, with 5-6 dexiotropal torsions (Plate III: Fd, S1-4). Strong spiral muscles are between torsions, obviously, making rotary movements at copulation. Remarks. The species Microstomum spiriferum Westbald is characterised by an accessory vaginal duct. That occurrence is unknown within the genus Microstomum. Therefore, this character needs the separation of Microstomum spiriferum from the genus Microstomum and the establishment of the new genus Einarmicrostomum gen. n. into which M. spiriferum is to transfer. Nomina nuda Microstomum sp. Den Hartog, 1966 nom. nud. Type locality. Het Zwin Nature Reserve and Bird Sanctuary, near Knokke Heist, Netherlands, EUROPE. Morphological notes unknown. Microstomum sp. Ferguson & Jones, 1949 nom. nud. Type locality. Norfolk, Virginia, USA. NEA. Habitat. Golf Course ponds, fresh-water. Morphological notes unknown. Microstomum sp. Gray and Rieger, 1971 Type locality. Stoupe Beck, Robin Hoods Bay,Yorkshire, England, North Sea, ANE; leg. Aug. 27 th, 1969; types: deposition not recorded. Habitat. Eulittoral benthal of an exposed sandy beach, grain size: M z φ between 1.89 and 1.96 and σi (sorting) between 0.54 and 0.55 (grain size determination after Folk 1968), marine. Microstomum sp. Gray and Rieger, 1971 Type locality. Filey Bay, Yorkshire, England, North Sea, ANE; leg. Sept. 2 th, 1969; types: deposition not recorded. Habitat. Eulittoral benthal of a semi-exposed sandy beach, grain size: M z φ 2.14, σi (sorting) 1.05 (grain size determination after Folk 1968), marine. 64

65 Remarks. The species Microstomum sp. Gray & Rieger found at Stoupe Beck Sand and Filey, western North Sea, could be identical with Microstomum spiculifer Faubel, 1974 which occurred at comparable beaches from Aug. to Nov. at the island of Sylt, eastern North Sea. Microstomum sp. Yanoviak, 2001 nom. nud. Locality. Barro Colorado Island, Lago Gatun, Panama, NEO; types: not prepared. Habitat. Water filled tree holes, freshwater. Morphological notes unknown. Remarks. Yanoviak (2001) tentatively identified a small worm as Microstomum sp. which was often very abundant; its densities were occasionally high enough (>20 ind./ml) to cloud the tree hole water. At lower abundance, Microstomum sp. formed yellowish aggregations on the edges of leaf litter and just below the water surface along the tree hole margin. Family Macrostomidae van Beneden, 1870 Diagnosis. Macrostomida without asexual reproduction. Male copulatory apparatus armed with or without stylet. Female apparatus simple; sclerotized, bursal organs absent. Type of the family: Macrostomum Schmidt, 1848 Key to the genera of Macrostomidae 1 pharynx simplex close behind brain 2 - pharynx simplex anterior to brain Omalostomum 2 bilateral ovaries present 7 - single ovary present 3 3 male copulatory apparatus with stylet 6 - male copulatory apparatus with cirrus or antrum masculinum 4 4 male copulatory apparatus with cirrus 5 - male copulatory apparatus with antrum masculinum Antromacrostomum 5 male copulatory bulb with cirrus internus Dunwichia - male copulatory bulb with cirrus externus Nynaeshamnia 6 (3: male copulatory apparatus with stylet) with single testis Bradynectes - with bilateral testes Haplomacrostomum 7 (2: bilateral ovaries present) male copulatory organ with sclerotised stylet 9 - male copulatory organ with cirrus or antrum masculinum 8 8 cirrus enclosed into muscle bulb 9 - with antrum masculinum not enclosed into muscle bulb Unsia 9 cirrus bulb of duplex type Psammomacrostomum - cirrus invaginated into prostatic vesicle, simplex type Siccomacrostomum 10 (7: male copulatory organ with sclerotised stylet) stylet without accessory stylet or lamellae 12 - stylet with accessory tubular stylet or lamellae stylet with accessory tubular stylet Bradburia - stylet with lamellae along stylet Velamacrostomum 12 (10: stylet without accessory stylet or lamellae) female system without accessory atrial duct 13 - female system with accessory duct Promacrostomum 13 discrete prostatic vesicle present Macrostomum 65

66 - reduced prostatic vesicle, its glandular ducts encased in proximal stylet Archimacrostomum Genus Macrostomum van Beneden, 1870 Diagnosis. Macrostomidae with tube-like penial stylet without any appendages like accessory stylets or lamellae, true prostatic vesicle and seminal vesicle. Female organs with vagina and seminal bursa joined via oviduct with the ovaries. Female gonopore anterior to male one. Type of the genus: Planaria appendiculata Fabricius, 1826 Remarks. Species of the genus Macrostomum are taxonomically determined mainly after its outline of the male stylet. The anatomy of the male and female genital apparatus is identical in most species of the genus Macrostomum and does not warrant a detailed description. The typical male complex consists of bilateral testes, vasa deferentia joining to a common vas deferens, seminal and prostatic vesicles joined by an intervesicular duct, and distal stylet. The prostatic vesicle is epithelially and musculary walled and its distal part more or less encased by the proximal part of the stylet. The stylet extends into a very small antrum masculinum. The female genital complex consists of bilateral ovaries, oviducts joining to a common oviduct, female genital atrium, vagina, and distal gonopore. Often, common oviduct and female atrium are not to discern. The distal vagina is surrounded by cement glands. If there are divergencies from these usual morphology then the divergencies will be described. New species will be described completely. Macrostomum hystricinum Beklemischev, 1951 (Plate V: A; Figs 21, 22; Tab. 1, 3, 4, 5) Synonymy. Planaria appendiculata Fabricius, 1826; p , pl. I, lit. B: figs 1-2. Macrostoma hystrix Oersted, 1843; p Macrostomum hystrix: Schmidt 1848; p. 54, pl. V: fig. 15. Turbella appendiculata: Diesing 1850; p Turbella hystrix: Diesing 1850; p Macrostomum erinaceum Girard, 1893; p Macrostomum ventriflavum Pereyaslawzewa, 1893; p. 244, pl. II: fig. 16. Macrostomum appendiculatum: Luther 1905; p. 80, pl. II: fig. 1. Type locality. Near Kopenhagen, Sjælland, Denmark, Belt; leg. Fabricius; types: USNM- W, (voucher specimen deposited by Ferguson). Habitat. Supra-, eu- and sublittoral benthal, limnocrene, rheocrene, sandy to muddy sediments, salt-marshes, salt-lakes, peat-bogs, moist humus soil, rock pools, down to 8m water depth (Lake of Geneva: 150m water depth (v. Graff 1913), rather eurytopic, eu-, poly-, and mesohaline, isolated brackish waters, freshwater. Geogr. distribution (freshwater). EUROPE: Austria (Innsbruck; Neusiedlersee, Steiermark), Belgian (Lille) Bulgaria (Plovtiv), Czechia (Prag), Danmark, Estonia, Finland (Lapland: near Muonioniska), France (Basses-Pyrenees: St.-Jean de Luz, Lac de Genève), Great Britain, Germany (Aschaffenburg, Axien, Elbe river, rivers in Saxonia, Holstein: saline marshes of Bad Oldeslohe, Thuringia: Numburger Rieth), France (Camargue) Hungary, Ireland, Iceland (Skútustaðir, Laugarvatn), Italy (Lago Maggiore, Lago di Garda, Pisa: Fiume Morto, ditch called Lamone near Tyrrhenian Sea), Latvia (Dorpat, Peipus), Makedonia (Lake Ohrid), Norway, Poland (Grzymaloew, Krakau, Warzaw, freshwaters of Prussia), Romania (Danube estuary - lagoon complex: Golovitza Lake, Sinoe Lake), Russia (RU-C: Moscow, RU-E: Orlov, Krestov, Ural: Orenburg, RU-KGD, RU-N: Kol Skiy Polyostrova: 66

67 Kandalaksha, Alexandrovsk, RU-S, RU-W: Kaluga; oblasts see Fig. x), Sweden (Östergötland, Lapland: Torne, Lappmark), Spain (Valencia, Albufera), Switzerland (Basel, swamps near Böhningen, Brienzer See, Lake of Geneva (?), Lago Maggiore), The Netherlands (Scheldt estuaries, Leyden), Ukraine; NEA: USA (Virginia); EPA: Kazakhstan (Aral Sea, Caspian Sea), Uzbekistan (Kasan), Siberia (Tomsk); NRE (Lake Gokca); AUS: Indonesia (Java: Buitenzorg; Tjibodas: Gowa Lalai, alt. 1,690m) (An Der Lan 1939, Ax 1951a, de Beauchamp 1910, Beklemishev 1917, 1922, 1927b, 1951, Braun 1885, 1894, Den Hartog 1974, 1977, Dorner 1902, Ferguson 1939a, 1954, Fuhrmann 1894, Fulinski & Szynal 1932, Gieysztor 1926, 1931, 1938, v. Graff 1913, Hallez 1890, v. Hofsten 1907, 1911, 1912, 1917, Jaeckel 1962, Kaiser 1974, Karling 1974b, Kawakatsu & Nishino 1994, Kraus 1965, Lanfranchi & Papi 1978, Luther 1960, Müller & Faubel 1993, Nasonov 1924, Nasonov 1919a, 1925, Papi 1951b, Reisinger 1933, Rixen 1961, Southern 1912, 1936, Steinböck 1926, 1933a, 1948, 1951b, Thienemann 1926, Valkanov 1926, Wegelin 1966, Young 1970). Geogr. distribution (brackish). ANE: Germany (Bad Oldesloe: salt-water pools 7.9 to 25.8 ), North Sea (North Frisian Islands: Sylt, salt-marshes; Belgium coast; Netherlands: Scheldt estuaries, Ameland), Skagerrak; English Channel (Salcombe estuary), Irish Sea (Isle of Man) North Channel (Millport), Kattegat; BAL: Germany (Greifswalder Bodden; Vitter and Schaproder Bodden; Kieler Bucht: Windebyer Noor, Bottsand, Nord-Ostsee-Kanal, Heiligenhafen, Schlei: Lindaunis, Selker Noor); Sweden (Stockholm: skerry-coast; Vrångö), Gulf of Finland (from Hangö eastwards to Modermagan) MED: Gulf of Lion (Etang de Canet), Spanish coast near Albufeira; Tyrrhenian Sea (Italy: close to Pisa, Gulf of Naples: Capo di Sorrento); Black Sea (Romania: Danube estuary: predeltaic region the melea St. George; Turkey: Sile; Ukraine: Crimea), Sea of Marmara (Küçük Çekmece); NRE: Caspian Sea (Azerbaijan: Baku, Lenkoran); ANW: Gulf of Maine (Canada: New Brunswig, Passamaquoddy Bay: St. Andrews, Pocologan, Deer Island, St. John, Campodello Island) (Armonies 1987, Ax 1951a, 1956a, 1959, Ax & Armonies 1987, Ax & Dörjes 1966, Beklemishev 1951, Den Hartog 1977, Gieysztor 1931, v. Graff 1913, Hellwig 1987, Jaeckel 1962, Kosler 1962, Lanfranchi & Papi 1978, Luther 1960, Mack-Firă 1968d, 1973, 1974, Nasonov 1924, Nasonov 1919a, b, Papi 1951b, Riedl 1956, Schockaert et al. 1989, Seifert 1939, Sick 1933, Tulp 1974, Westblad 1953). Morphological notes. Body length up to 2.0mm by 0.25mm width, blunt or bluntly rounded anterior end and spatulate posterior end when attached to substrate; colourless with the exception of that colour imparted by intestinal contents. Tail bordered with adhesive glands. Rhammite glands located around brain, produce rhammites which migrate in tracks to the anterior margin. Adenal rhabdites grouped from 2 to 10 scattered over dorsal surface; in tail region larger rhabdites in groups of two and three more numerous. Small rhabdites, spindle-shaped, pointed on both ends, surround border of mouth. Eyes in dorso-posterior position of brain. Sensory hairs and spines space regularly along margin. Protonephridial system composed of two longitudinal main branches extending laterally; excretion pores close behind mouth. After Ferguson (1937, p. 29) main lateral branches unite in the posterior just behind the point of the male stylet. Ring of pharyngeal glands enter pharynx simplex above mouth. Intestine with weak, bi-layered muscle wall; Minotian cells ( Körnerkolben ) present. Faint muscle fibres connect intestine with body muscle wall. Chromosome number n = 3. Reproductive system with bilateral testes and ovaries. Vasa deferentia join to common vas deferens which could dilate to false seminal vesicle. Stylet (Plate V: A) proximally funnellike, gradually narrowing distad from a widened, crenated base and terminating in a distal right angle bend; the opening is located in the convexity of the curve, subterminal to the pointed tip; measurements of stylet: d = 59.8µm, a = 19.5µm Length after Kaiser (1974) 45-60µm (dissimilar d). Gonopores separate. Female system as usual. Female atrium with inconspicuous cellular closure apparatus rostrally. Eggs yellow-brown when deposited. 67

68 Remarks. Luther (1960, p. 68) designated the species Macrostomum hystrix Oersted, respectively M. appendiculatum sensu von Graff (1905), a collective species, which in part resolve into several well described species, respectively subspecies (cf. Papi 1951b, 1953, Ferguson 1954). Fabricius (1826) described a sexually immature macrostomid species which he called Planaria appendiculata. However, he never saw sexually mature specimens. Oersted (1843), on the contrary, described Macrostoma hystrix based on sexually mature specimens developing a bow-shaped stylet being proximally funnel-shaped. However, the stylet was drawn very diffuse so that a recognition of the species was impossible later on. On the basis of these facts, Beklemishev (1951) decided to re-establish distinctness by creating the new name, Macrostomum hystricinum and to state Planaria appendiculatum Fabricius, 1926 and Macrostomum hystrix Oersted, 1843 as being synonyms of M. hystricinum Beklemishev, Ecological notes. Macrostomum hystricinum lives in limnetic and brackish water areas with salinities up to 12 (Schlei, Kieler Bucht, Ax 1951a). After Hellwig (1987), M. hystricinum settled muds being rich in detritus and grown with Spartina anglica (Schreb.), Suaeda maritima (L.) and/or Salicornia ssp. in the supralittoral of the island of Sylt (eu- to mesohalinicum). A maximum value of abundance averaged 11.5 ind./10cm², was recorded on a sand bar grown with Spartina anglica. In mud, the abundance varied between 1 and 4 ind./10cm² as an average. Macrostomum hystricinum marinum Rieger, 1977 (Plate V: B) Type locality. Anne McCrary, North Carolina, USA, ANW; types: deposition not recorded. Habitat. Eulittoral, benthal, mud, marine. Geogr. distribution. ANW: USA (North Carolina: Onslow Bay, White Oak river; Bogue Banks: Pine Knoll Shore; Florida Keys: Pigeon Key), Canada; MED: Ligurian Sea (Italy: La Spezia, Fiascherino); Black Sea (Danube estuary: Sahalin island), Adriatic Sea (Rieger 1977). Morphological notes. Body length up to 1.0mm, anterior end roundish, posterior end with distinct plate. Sensory bristles concentrated on anterior end, 5-10µm long, and along margin of adhesive plate, here about 20µm long. Paired eyes with sometimes brownish pigment granules in the epidermis. Rhammites 5-10µm long. Rhabdites, 4-10µm long, particularly concentrated on the dorsal epidermis of the adhesive plate. Pharyngeal gland ring with two kinds of glands, tiny rounded secretory granules (<1µm) and long slender sticks (2-5µm long). Adhesive plate with U-shaped field of papillae; papillae average 8µm in length. North American populations exhibited about 300 adhesive tubules around the rear plate and one European specimen (Fiascherino, Italy) about 100 adhesive tubules. Food diatoms. Sperms without lateral processes, 30µm total length (North American population). Stylet (Plate V: B). Macrostomum acre Wang, 2005 (Plate VII: J) Synonymy. Macrostomum acus Wang, 2005; p , figs Type locality. Pond located downstream of Chican Reservoir, Chican District, Zhanjiang City, Guangdong Province, China (21.18 N; E), EPA; leg. Dec. 2003; types: RISU- CH, ZJCK III-1 (holotype) ZJCK III (paratypes). Habitat. Freshwater. Morphological notes (m.l.s.). Body length up to 2.56mm by 0.45mm width in mid-body, anterior end bluntly pointed, posterior end with bluntly rounded adhesive plate, colour milky white in i.l., transparent in t.l. Intestine yellow taking on colour of food content. Anterior end 68

69 with slight constriction at level just anterior to brain and waisted at level of male organs. Anterior and posterior body-end with bristles. Eyes kidney-shaped; distance between eyes 100µm. Anterior and posterior body-end with rigid bristles; along posterior margin 6-10 bristles, 13-20µm in length. Rhabdites in bundles with 2-9 rods, 14-18µm long. Bundles of sensory cilia, up to 3 cilia, 10-14µm long, only along anterior margin. Reproductive system with bilateral testes and ovaries. Vasa efferentia separately join forming a common vas deferens which is strongly distended to a false seminal vesicle based on high sperm production. Seminal and prostatic vesicle immediately connected with each other; intervesicular duct absent. Distal part of the prostatic vesicle not encased by the proximal stylet. Sclerotised stylet straight, tube-like, d = µm, a = 16-18µm, e = 11µm, decreases gradually distad from the proximal base (Plate VII: J). Distal opening of stylet subterminal. Diameter of the tube at level of distal opening 5µm; distal tip of stylet thickened, 13µm in length and 3µm in diameter. Macrostomum acutum Ax, 2008 (Fig. 32; Plate X: T) Type locality. Morgan Park (East Bay Park), northern part of Winyah Bay, Georgetown, South Carolina, USA, ANW; leg. Prof. Dr. Ax, Okt. 1996; types: deposition not recorded. Habitat. Eulittoral benthal, sandy beach, salinity range 0.1 to 5.5, oligohaline. Fig. 32. Macrostomum acutum. Stylets of different specimens (after Ax 2008). Morphological notes. Body length up to 1.0mm, colourless; eyes absent. Reproductive system. Stylet straight, walls of which of the proximal two-thirds parallel; distal third decreasing to a pointed tip (Fig. 32); distally, stylet with oblique opening which give way to a proximad directed spike at the convexe side; d = 68-72µm, e = 8-9µm; length of the spike 12µm (one measurement). Macrostomum aegyptium Beltagi, 1972 (Plate VI: *B) Type locality. Shebin El Kanater, 25km far from Cairo, Egypt, Africa; leg. July to Aug. 1969; types: private collection. Habitat. Sublittoral phytal, Eichhornia spp., Elodea spp., Ceratophyllum spp., Potamogeton spp., freshwater. Morphological notes. Body length up to 2.0mm, rounded terminal ends, posterior adhesive disc, pale white (i.l.). Reniform eyes present. Rhammite glands located laterally of brain the tracks of which unite at anterior body-end. Adenal rhabdites, 11µm in length, scattered in large numbers over body surface. Epidermis with intra-epithelial nuclei and adenal cyanophilous glands. Body muscle wall structured as usual; dorso-ventral muscle fibres present. Intestine walled with outer longitudinal and inner circular muscle fibres. Nervous system with brain, two pairs of nerve stems extending anteriad, one pair of lateral nerve stems extending posteriad, and with nerve ring around distal pharynx. Reproductive system with bilateral testes and ovaries. Vasa deferentia unite to form a false seminal vesicle (common vas deferens); false seminal vesicle walled with bi-layered muscle sheath. Seminal and prostatic vesicle joined by intervesicular duct. Stylet, 394µm in length, 69

70 tubular, slightly tapering distad. Distal tip with tuba-like thickening. Female system with common oviduct separated from female atrium by a cellular sphincter. Macrostomum amaniensis Young, 1976 (Plate VIII: K) Type locality. Lake Amani, Tanzania, Africa; leg. 19. March 1972; types: BMNH-L Habitat. Sublittoral phytal, freshwater. Morphological notes (Plates IV: K). Body length up to 1.3mm, macrostomid-like, extremities rounded, posteriorly with adhesive glandsreaching a size of 14µm, whitish or pale yellowish (i.l.). Semi-rigid bristles on anterior margin up to 13µm; sensory hairs, single or in groups of up to 4, reach maximum length of 20µm; they are distributed sparsely over body surface. Rhabites single or in bundles of up to 9 rods but most commonly 3 to 5. Rhammite tracks present. Paired eyes at caudal border of brain. Reproductive system with bilateral testes and ovaries. False seminal vesicle separated by slight constriction from round seminal vesicle. Intervesicular duct present. Stylet (Plate VIII: K), bow-shaped, gradually tapering in diameter distad, is distally swollen as in M. tuba. Stylet measurements: a = 14µm, d = 160µm and e = 5µm. Female system as usual. Female atrium with distinct cellular closure apparatus rostrally. Vagina medium-sized. Cement glands round the vagina present. Macrostomum amurensis Beklemishev, 1950 (Plate X: K) Type locality. Flood-plain of Amur river, opposite to Khabarovsk, Russia, EPA; leg. 19. June 1937; types: deposition not recorded. Habitat. freshwater. Morphological notes. Body length up to 1.5mm, anterior end rounded, posterior end macrostomid-like, spatulate with adhesive glands. Black eyes. Intestine yellowish due to tinged rhabdites. Reproductive system with bilateral testes and ovaries. Testes elongated at level of first half of intestine. Female opening behind gut. Stylet (Plate X: K) composed of straight, elongate funnel with distal hook-like bend turned at an angle of about 90 between hook and main axis; distal tip of stylet slightly aslant sectioned, the edge of its terminal opening with very typical groove; length of stylet about 150µm. Stylet directed strictly to the caudal body-end. Macrostomum axi Papi, 1959 (Plate V: Q) Type locality. S. Rossore near Pisa, Italy, Europe; leg. Febr. 1955; types: depostion not recorded. Habitat. Mid-littoral benthal, 30cm above water-line, sand, down to 5cm sediment depth, salinity 1-16, meso-, oligohaline. Morphological notes. Body length up to 0.8mm, bluntly rounded anteriorly, spatulated posteriorly; caudal adhesive glands present. Tactile bristles around anterior body-end, 8-10µm long, and around posterior body-end. Rhammite tracks and rhabdites present. Eyes absent. Body muscle wall structured as usual. Reproductive system with bilateral testes and ovaries. False seminal vesicle separated from seminal vesicle by distinct constriction marked by strong circular muscle fibres. Short intervesicular duct present. Stylet (Plate V: Q), tubular, gradually tapering in diameter distad, 70

71 proximal part slightly arcuate, and distal part slightly spiral. Distal tip of stylet acuminate, turned at an angle of about 90 from the main axis forming a twisted concave bend. Opening subterminal on the convex surface. Measurements of stylet: a = 12µm, 88µm length of extremities. Female atrium with tall cells, non-ciliated, and with rostral closure-cells to the oviducts; common oviduct absent. Macrostomum balticum Luther, 1947 (Plate V: C, Figs 20, 33, 84; Tabs 4, 5, 10) Synonym: Macrostomum spirale Meixner nom. nud. Schulz & Meyer, 1939; p Type locality. Near Henriksberg, Finland, Gulf of Finland, BAL; leg. T.G. Karling, 18. June 1934; types: deposition not recorded. Habitat. Supra-, eu- and sublittoral sand and mud, salt-marshes, down to 3m water depth, eu-, poly-, and mesohaline. Geogr. distribution. BAL: Baltic Proper (Sweden, Södermanland: Torö, Nämndö; Ostergotland: Gränsö; Skåne: Åhus); Gulf of Finland (Tvaerminne: Henriksberg, Vikarskär, Långholmen, Jovskär, Kvarnskär), Kieler Bucht (Bottsand, Nord-Ostsee-Kanal); ANE: Skagerrak (Gullmarfjord: Kristineberg; Fiskebäckskil, Halland: Laxvik); North Sea (North Frisian Islands: Sylt, Amrum; Faroe Islands: Bight of Hvalvik; Norway: Trondheimsfjord, Selva; Netherlands: Scheldt estuaries, south of Bergen op Zoom, Knokke Heist, Texel; Belgium: Bredene, Zwin, Dievengat; France: Wimereux, Ambleteuse, Bassin d Arcachon); English Channel (England: river Avon estuary, Aveton Gifford); ASW: Caribbean Sea (Jamaica: Discovery Bay) PNE: Alaska (Kotzebue); PNW: Japan? (Honshu: Aomori District, Obuchi Pond) (Armonies 1987, 1988a, Ax 1951a, 1960, 1995a, 2008, Ax & Armonis 1990, Bilio 1964, Den Hartog 1965, 1966, 1974, 1977, Faubel 1977a, Fig. 33. Macrostomum balticum. Stylets from different sites. A. Kieler Bucht. B. Faroes. C. Japan: Obuchi Pond. After Ax Hellwig 1987, Karling 1974b, Luther 1960, Schockaert et al 1989, Schütz 1966, Schulz & Meyer 1939, Therriault & Kolasa 1999, van der Velde 1976, Van der Velde & Van der Winkel 1975, Westblad 1953). Morphological notes. Body length up to 1.25mm, with macrostomid outline, colourless, transparent; anterior body-end rounded, sometimes pointed; posterior end spatulate, rounded, with adhesive glands. Terminal ends with tactile bristles, anterior bristles about 12µm long. Rhabdites lacking, Rhammite tracks and eyes present. Reproductive system with bilateral testes and ovaries. False seminal vesicle present; transition of seminal and prostatic vesicle marked by a constriction; intervesicular duct absent. Stylet (Fig. 33), 73-80µm in length (? d), tube-shaped funnel, slightly spiral with widened proximal base and distal pointed hook; the latter is bent at an obtuse angle from the main axis. Distal opening at the tip of the main axis. Female atrium with tall cells, small muscle wall, and distally with cilia. Closure apparatus see Fig. 20C, comparable the bursal mouth of Acoela. Remarks. Ax (1992, 2008) described Macrostomum balticum from northern Japan with carefulness. The stylet (Fig. 33 C) corresponds in length and form largely the stylets of specimens from northern Europe (Fig. 33 A, B). However, the length of the distal tip of the stylet from Japanese specimens is halfway in length of the European ones (Fig. 33 C). Ecological notes. Macostomum balticum was observed by Hellwig (1987) in lentic habitats of the North Frisian Island Sylt in the supralittoral belt consisting of detritus rich muddy and 71

72 sandy sediments. Maximum values were found in July on sand, 156 ind./10cm², and on mud, 167 ind./10cm² (Fig. 83). Autecological characterisation. Lentic slack water inhabitant from poly- to mesohaline waters. Macrostomum balticum meridionale Papi, 1953 (Plate V: D) Type locality. S. Rossore, near Pisa, Italy, Europe; leg. 26. March 1953; types: deposition not recorded. Habitat. Temporarily flooded pools, T = 15.5 C, ph = 8.8, salinity = 2, oligohalinicum. Morphological notes. Body length up to 1.0mm, macrostomid-like, colourless (t.l.), whitish (i.l.), extremities rounded and provided with tactile bristles (about 13µm in length); posterior end with adhesive papillae and bundles of adenal rhabdites, 18-21µm long; each bundle with 4-5 rhabdite rods; otherwise rhabdites single and very rarily dispersed over the body. Microrhabdites, 5µm in length, arranged around rim of the mouth. Reproductive system with bilateral testes and ovaries. Intervesicular duct present. Stylet tube-shaped, curved (not spiral) funnel with widened proximal base gradually decreasing distad. Distally, a spiral (obvioulsy movable) lappet or hook (Plate V: D), 16-18µm long, is affixed at an obtuse angle to the main tube. Distal opening terminal at the tip of the main axis. Measurements of stylet (Plate V: D): d = 90µm, a = 21µm, e = 6-8µm. Oviducts unite mediad to common oviduct; transition to female atrium closed by cellular stopper. Macrostomum baringoensis Young, 1976 (Plate V: I) Type locality. Near Kampi ya Samaki, Lake Baringo, Kenya, Africa, ETR; leg. 16. Dec, 1971; types: BMNH-L, Habitat. Littoral, freshwater. Morphological notes. Body length up to 1.1mm, extremities rounded, posteriorly slightly spatulated with adhesive glands, colourless though gut appears very pale yellow. Semi-rigid bristles occur singly or in pairs, up to 20µm in length, along lateral margin; anterior body-end with bristles of up to 9µm length. Rhabdites single or in bundles of up to 14 rods but most commonly 4 to 8 rods. Rhammite tracks present. A pair of eyes at posterior border of crescent brain. Body muscle wall structured as usual; dorso-ventral muscle fibres present, particularly in the posterior body-end. Excretory system with two coiled stems with branching ducts; external opening not observed. Pharynx thin-walled, ciliated, and with surrounding glands proximally at transition into the intestine. Intestine walled with bi-layered muscle sheath, i.e. inner circular and outer longitudinal muscles. Reproductive system with bilateral testes and ovaries. Paired oviducts join to common oviduct which extend into female atrium. The passage from oviduct into female atrium is formed by well-developed closure-cells. Vasa deferentia join to common vas deferens which enters the seminal vesicle. False seminal vesicle absent. Seminal and prostatic vesicle joined by intervesicular duct. Extra-vesicular prostatic glands around the prostatic vesicle but not too distinct, enter close to the intervesicular duct the prostatic vesicle. Stylet (Plate V: I) with distal bend forming a more or less a right angle between the distal end and the main axis. Distal tip constitutes thickened wall of the tube. Distal opening at the heel of the stylet. Stylet measurements: a = 11 to 17µm, length 73 to 85µm, e = 5 to 9µm, distal tip 7 to 10µm. Macrostomum bellebaruchae Ax, 2008 (Plate XI: H) 72

73 Type locality. Hobcaw Barony, Winyah Bay, Georgetown, South Carolina, USA, ANW; leg. Prof. Dr. Ax, April 1998; types: deposition not recorded. Habitat. Eulittoral benthal, clear medium sand, oligohaline to freshwater. Morphological notes. Body length up to 1.2mm, colourless, with adhesive glands and rhabdites. Eyes absent. Reproductive system. Male copulatory apparatus with seminal and prostatic vesicle joined by a short intervesicular duct. Prostatic vesicle with extravesicular glands; prostate not encased in proximal stylet. Proximal half of stylet developed as longish funnel (Plate XI: H); distal half spiral with two identical bends. Distal opening of the stylet terminal without thickened fringe; d = 56µm. Macrostomum bicurvistylum Armonies & Hellwig, 1987 (Plate X: I; Tab. 5) Type locality. Salt-marsh, Kampen, Sylt, North Frisian Islands, North Sea, ANE; leg. Sept. 1982; types: deposition not recorded. Habitat. Supralittoral benthal, mud, salt-marsh, brackish, marine. Geogr. distribution. PNE: Alaska (Kenai Peninsula: Seward, Fourth of July Beach, Lowell Point) (Ax & Armonies1990). Morphological notes (Sylt specimen). Body length up to 1.5mm, extremities rounded and outline not typically macrostomid-like. Bristles absent. Small eyes with few granules of pigment at posterior border of crescent brain. Rhabdites in bundles of 6 to 10 over entire body. Rhammite tracks absent. Reproductive system with bilateral testes and ovaries. Stylet (Plate X: I) twofold bent tube, 105 to 148µm in length (diagonally), proximal opening funnel-shaped, a = 20µm, distal opening e = 5µm. Morphological notes (Alaska specimen; reported only differences to Sylt specimens; cf. also Ax 2008, p ). Body length up to 4.0mm, normal length about 1.0mm, typically macrostomid-like with bluntly rounded anterior end and rounded posterior end. Posterior end spatulate with constriction posterior to last oocytes. Stylet 120 to 148µm in length (diagonally), proximal opening a = 20-25µm, distal opening e = 6-7µm. In the photographs of figure 5 (Ax & Armonies 1990, p. 15), there is clearly to see that the distal bend of the stylet turned distinctly from the main axis. Macrostomum boreale Riedel, 1932 (Plate IX: P; Fig. 20) Synonymy. Macrostomum anocele Riedel, 1932; p. 38, 81 (typographical error). Type locality. Godhavn, Disko Island, Greenland, Davis Strait, ANW; types: Habitat. Eulittoral, benthal, rockpools filled with debris of Basalt, marine. Morphological notes. Body length up to 1.0mm, anterior end blunt, slightly trilobed, posterior end spatulate with constriction behind gut, colourless. Rhammite glands, dorsal to brain, present; tracks open to the exterior at anterior margin. Rhabdites scattered over entire body surface. Eyes absent. Cerebral glands located caudal of rhammite glands; the ducts of which extend ventrally to the anterior end. Epidermis with intra-epithelial nuclei; basal membrane not recognised. Body muscle wall structured as usual; dorso-ventral muscle fibres, in particular, in anterior and posterior end. Pharyngeal glands enter distal part of the pharynx. Reproductive system with bilateral t estes and ovaries. Vasa deferentia unite in false seminal vesicle which is connected via a common vas deferens with the seminal vesicle. Intervesicular duct present. Male genital atrium serving the stylet, ciliated. Stylet (Plate IX: P) 73

74 120µm in length (d), funnel-shaped, after one fourth of total length from proximal base with approximately right angle bend; distal opening subterminal, oblique. Macrostomum brevituba Armonies & Hellwig, 1987 (Plate VI: F; Tabs 5, 10) Type locality. Nielönn, Kampen, Sylt, North Sea, ANE; types: deposition not recorded. Habitat. Supralittoral benthal, mud, salt-marshes (Puccinellia maritima (Hudson) Parl.), brackish, marine. Morphological notes. Body length up to 1.2mm, bluntly rounded anteriorly, rounded posteriorly. Eyes absent. Reproductive system with bilateral testes and ovaries. Stylet (Plate VI: F), 60 to 70µm long tube, distad tapering from a = 26-32µm to e = 12µm. Distal opening of stylet truncated; distal tip ring-shapedly thickened. Macrostomum burti Ax & Armonies, 1987 (Plate X: J) Type locality. Northern Harbor, Deer Island, New Brunswig, Canada, ANW; leg. P. Ax, 13. Aug. to 11. Sept ; types : ZMU-G, P 1951 (holotype), P (paratypes). Habitat. Eu- and supralittoral benthal, fine to coarse sand, sand mixed with mud or detritus, salt-marsh, brackish, marine. Geogr. distribution. ANW: Gulf of Maine (Canada: New Brunswig, Pocologan, Sam Orr Pond, Campobello Island, Baie des Chaleurs: Miguasha cliff, Elmtree River estuary) (Ax & Armonies 1987). Morphological notes. Body length up to 1.2mm, without pigmentation. Eyes present. Feeding on diatoms. Reproductive system. Stylet (Plate X: J) tube-shaped, 45-53µm in length, distad somewhat tapering with distal opening, e = 2µm, cut off; proximal opening a = 9-10µm. Stylet evenly walled without thickenings. Distal third of tube bent; according to the figures 5 C-F (Ax & Armonies 1987), the longitudinal axis evidently runs not in one plane. Ecological notes. Macrostomum burti lives in low energy areas ranging from eulittoral to supralittoral salt-marshes (Ax & Armonies 1987). Macrostomum cairoensis Beltagi, 1972 (Plate VI: *C) Type locality. Pond near Shebin El Kanater, Egypt, Africa; leg. July to Aug. 1969; types: deposition not recorded. Habitat. Sublittoral, phytal, Eichhornia crassipes (Mart.) Solms, Elodea canadensis L.C. Rich. in Michx., Ceratophyllum sp., Potamogeton sp., freshwater. Morphological notes. Body length up to 3.0mm, anteriorly bluntly rounded, posteriorly disk-like with constriction at level of male apparatus. Adhesive glands present. Lateral rhammite tracks unite just before frontal end. Two reniform eyes close to each other at dorsocaudal border of brain. Epidermis with intra-epithelial nuclei and adenal rhabdites being single or in bundles of 2 to 4 rods; rhabdites most abundant dorsal and at the extremities. At spatulate end, ventral epidermis with adenal rhabdites. Body muscle wall structured as usual; dorso-ventral muscle fibres present. Alimentary canal structured as usual; intestine walled by bi-layered muscle sheath. Excretory system not observed. Reproductive system with bilateral testes and ovaries. Vasa deferentia unite to form a false seminal vesicle walled with faint outer longitudinal and inner circular muscle fibres. False 74

75 seminal vesicle joins with seminal vesicle via small constriction. Seminal vesicle with threelayered muscle wall. Extravesicular prostatic glands enter the proximal part of the prostatic vesicle in common with the intervesicular duct. Stylet (Plate VI: *C) an about 490µm long, curved, wavy tube with distal tuba-like thickening. If the longitudinal axis of the tube is running in one or more planes was not given. Female system as usual. Female atrium with distinct cellular closure apparatus rostrally. Gonopores separate. Fig. 34. Macrostomum calcaris. Stylets of different specimens (after Ax 2008). Macrostomum calcaris Ax, 2008 (Fig. 34, Plate: X: P) Type locality. Mouth of Sampit River, Maryville, Georgetown, Winyah Bay, South Carolina, USA, ANW; leg. Prof. Dr. Ax, April 1998; types: deposition not recorded. Habitat. Supralittoral benthal about 30cm above midwater line, sand, salinity about 15, brackish water. Other specimens. Morgan Park (East Bay Park), northern part of Winyah Bay, South Carolina, USA, ANW. Morphological notes. Body length up to 0.8mm, with well developed rhabdites, in particular, in posterior body, eyes absent. Reproductive system. Stylet more or les straight but medially very faintly s-shaped undulated (Fig. 34); distal opening terminal, arcuately incised; d = 80-88µm. The distal part of the tube give way to a contorted spike having a length of 32 40µm. The distal end of the spike evidently firms up a faintly reinforced vesicle (Fig. 34 ve). Macrostomum caprariae Papi, 1959 (Plate X: F) Type locality. Isola di Capraia, Italy, Europe; leg. 18. Aug. 1954; types: deposition not recorded. Habitat. freshwater. Morphological notes. Body length up to 0.8mm, macrostomid-like in shape, stubby, anteriorly truncated, tail region spatulate with disk-shaped, rounded posterior end; waist at level of male organs; posterior end with adhesive glands. Tactile bristles, 10µm long, around anterior and posterior margin. In i.l. colourless, intestine whitish. Rhabdites scattered in groups of 6 or more rods over entire body surface; dorsally, rhabdites more numerous than ventrally. Rhammite tracks present. Eyes in dorso-posterior position of brain. Intestine with Minotian cells. Reproductive system with bilateral testes and ovaries. False seminal vesicle present. Seminal vesicle surrounded by strong circular muscle wall, joined with prostatic vesicle via an intervesicular duct. Stylet (Plate X: F) funnel-shaped, distad tapering and evenly turning; distal end slightly dilated. Distal opening terminal. Measurements: a = 38µm, d = 106µm, e = 3.5µm. Remarks. Papi (1959, p. 87) described that the prostatic vesicle of Macrostomum caprariae present various forms depending on sexual maturity. In sexually mature specimens, it seems that the walls of the prostatic vesicle are reduced. The vesicle reduced, forms a cluster of glands ( cupola Papi) lying just anterior to the proximal part of the stylet, and their glandular ducts are encased by the proximal funnel of the stylet. That would mean the species possesses 75

76 a reduced prostatic vesicle and has to be transferred to the genus Archimacrostomum Ferguson. However, I desist from doing that because Papi presented only a supposition ( la parete della vesicula appare ridotta a formare una cupola sulla porzione prossimale imbutiforme dell organe cuticolare ) and did not verify the reduction of the prostatic vesicle in his Fig. 2. In his figure the prostatic vesicle displays a true lining. Macrostomum carolinensis (Ferguson, 1940) Ferguson 1954 (Plate XI: *F) Synonymy. Macrostomum ruebushi var. carolinense Ferguson, 1940; p , figs Type locality. Cohen estate, Blowing Rock, North Carolina, USA, NEA; types: deposition not recorded. Habitat. Littoral phytal, spring-fed lake, altitude of feet, freshwater. Morphological notes. Body length up to 1.0mm, macrostomid-like in shape, anteriorly truncated, a pair of convexities at level of mouth and tail region being spatulate with slightly pointed end. Body colourless except for the yellow-green gut due to algae ingested. Rhammite tracks present. Epidermis very densily supplied with rhabdites. Sensory hair-tufts space regularly lateral margin; terminally spines present, the posterior of which about twice the length of those of frontal margin. Rhabdites tickly spread over body surface in groups of from 2 to 8. Large, black eyes present. Excretory system with lateral convoluted tubules; subsidiary branches and flame cells present; external pores not detected. Mouth amply supplied with mucous glands radiating the ciliated border of the mouth. Reproductive system with bilateral testes and ovaries. Vasa deferentia join immediately entering the seminal vesicle. Prostatic vesicle with ciliated pits. Stylet funnel-shaped with distal bend; the long oval subterminal opening takes the entire convex end of the bent portion; proximal base crenated. Gonopores separate. Female genital system developed as usual; common oviduct present. Macrostomum caudatum Uljanin, 1870 Type locality. Pawlowsky Island, Sevastopol, Black Sea, MED; types: unknown. Habitat. Sublittoral benthal, 10m water depth, marine. Morphological notes. Body length up to 1.0mm, typically macrostomid-like, anteriorly rounded, posteriorly spatulate with adhesive glands. Colour slightly yellow, gut darker yellow. Rhabdites present. Spines along anterior margin. Eyes absent. Reproductive system with bilateral testes and ovaries. Seminal vesicle with slightly bent stylet. Remarks. Uljanin (1870) described a typical macrostomid species, however, he reported that M. caudatum has developed a statocyst. The possession of a statocyst induced von Graff (1882) to transfer the species to the genus Mecynostomum Van Beneden, 1870 of the order Acoela. The development of a statocyst, however, must have been an erroneous interpretation of the inner organs of the specimen studied by Uljanin. Macrostomum christinae Young, 1976 (Plate VII: Q) Type locality. Kitenkela/Athi River, Kenya, ETR; leg. 30. March 1972; types: BMNH-L, Habitat. Sublittoral, freshwater. Geogr. distribution. ETR: Tanzania (Usambara Mts.: Lake Amani) (Young 1976b). 76

77 Morphological notes. Body length up to 0.9mm, typically macrostomid-shaped, extremities rounded, distinct waist at level of stylet, colourless (t.l.), whitish (i.l.). Posterior end with adhesive glands. Semi-rigid bristles single or in tufts of up to 6 along lateral margin; they vary in length up to a maximum of 18µm; anterior end with bristles, up to 11µm long. Rhabdites scattered in groups of 1 to 8, though mostly 2 to 5, over entire body surface. Rhammite tracks were not observed. Eyes in dorso-posterior position of brain. Reproductive system with bilateral testes and ovaries. False seminal vesicle absent. Seminal and prostatic vesicle joined by intervesicular duct. Extravesicular prostatic glands present. Stylet (Plate VII: Q) more or less straight diminishing in diameter towards distal end; the latter slightly bent and the wall slightly thickened. Measurements: length 78µm in one specimen but averaged 72µm, a = 10µm, e = 3µm in slightly squashed sspecimens. Female system as usual. Female atrium with inconspicuous cellular closure apparatus rostrally. Macrostomum clavistylum Beklemishev, 1951 (Plate VI: S) Type locality. Ai-Dai Lake, Troizka, Russia, EPA; leg. V.P. Baskina, 12. July 1926; types: deposition not recorded. Habitat. Sublittoral benthal, sandy sediments, littoral lakes, freshwater. Geogr. distribution. Europe: Romania (Danube estuary, Racelm Sinoë: Tasaul Lake) (Mack-Firă 1974). Morphological notes. Macrostomum clavistylum is greatly similar with M. hystricinum but specimens are larger. Very many rhabdites are distributed over the body; anterior body end with rhammite tracks. Eyes red, measuring 10 x 15µm. Reproductive system with bilateral testes and ovaries. Stylet (Plate VI: S), d = 150µm long, bow-shaped with proximal oblique funnel and distal gutter-shaped, spiral end; terminal tip of the stylet with acute pike bent concavely over the subterminal opening. Remarks. Stylet of M. clavistylum comparable to M. catarractae Gieysztor, 1938 (Kolasa 1973a). Macrostomum clavituba Ax, 2008 (Plate VI: N; Fig. 35) Type locality. Etang de Salses, Gulf of Lion, MED; leg. Prof. Dr. Ax, Sept. 1962; types: deposition not recorded. Habitat. Supralittoral benthal about 30cm above mid-water line, sand, salinity about 15, brackish water. Morphological notes (Fig. 35A). Body length up to 1.2mm; eyes just anterior to pharynx. Reproductive system with bilateral testes and ovaries. Male copulatory apparatus with seminal and prostatic vesicle joined by a short intervesicular duct. Prostatic vesicle with extravesicular glands; prostate not encased in proximal stylet. Curved stylet of tuba type (Fig. 35B-D); distally, opening of the stylet thickened at the convexe side; d = 70-75µm. Macrostomum collistylum Ferguson, 1939 Type locality. Spring near Whittle Springs Road, Knox County, Tennessee, USA, NEA; types: USNM-W, 20436, Habitat. fluviatile, freshwater. Morphological notes. Body length up to 0.5 mm, macrostomid outline, terminally rounded but posterior one more bluntly rounded, posterior end spatulate with waist caudal of gut, 77

78 Fig. 35. Macrostomum clavituba. A. Dorsal view in quash preparation. B. Male copulatory apparatus. C. and D. stylets of two different specimens. Scale lines A 100µm; C 10µm. After Ax colourless. Rhabdites in groups from 8 to 12. Spines absent. Hairs in small tufts space sparsely along margins. Eyes reddish-brown, embedded in caudal tissue of brain. Protonephridia with lateral stems. Epidermis with peculiar type of cell in great numbers. Sperm cell 32µm without postero-lateral setae. Reproductive system with bilateral testes and ovaries. Vasa deferentia join immediately before entrance of seminal vesicle. False seminal vesicle absent. Stylet is so coiled, that only a part could be focused upon in visual plane. The coiling of the stylet involving an arc, is of approximately 315. From proximal, the stylet is gradually tapering to a pointed tip. Proximal base crenate. Female system as usual. Gonopores separate. Macrostomum coomerensis Faubel & Cameron, 2001 (Plates IV: F, VI: H) Type locality. Coomera salt-marsh, S, E, Gold Coast, Queensland, Australia; leg. B. Cameron, April 1998; types: QM-B G (holotype), G (paratypes). Habitat. Epilittoral salt-marsh pools, bordered by Sporobolus virginicus (Kunth.) and Sarcocornia quinqueflora (ex. Ung. Stern), mud mixed with negligable sand, polyhalinicum, euhalinicum. Morphological notes. Body length up to 1.4mm by 0.25mm width, extremities rounded, greatest body-width behind mid-body, posterior end not typically spatulated (Plate IV: F). Caudal end of body with adhesive glands and dense aggregates of large rhabdites, 10.7µm in 78

79 length. Rhabdites evenly distributed in serial lines over body. Marginal spines or ciliary tufts absent. Eyes black, positioned at posterior border of crescentic brain. Cerebral glands not reaching anterior level of brain, open at frontal margin. In i.l. colour brownish yellow with contrasting darker lateral ovaries; in t.l. colour greyish with yellowish digestive system. Epidermis with adenal nuclei; basal membrane not observed, probably absent. Pharynx with extrapharyngeal glands; intestine with less numerous cilia than pharynx. Reproductive system with bilateral testes and ovaries. Vasa deferentia join to common vas deferens on the right side before entering seminal vesicle. Intervesicular duct present. Distal prostatic vesicle encased in proximal portion of stylet. Stylet (Plate VI: H), proximally slightly funnel-like extended with crenated base, distal two thirds spiralled, measures 125.0µm (d) in length. Distal tip of stylet thickened, opening of which subterminal. Female system as usual. Female atrium distally ciliated and rostrally with cellular closure apparatus to the common oviduct. Gonopores separate. Macrostomum coxi Young, 1976 (Plate VI: I) Type locality. Lake Naivasha, Kenya, Africa, ETR; leg. Dec to July 1972; types: BMNH-L, Habitat. Sublittoral phytal, freshwater Geogr. distribution. ETR: Kenya (Nairobi: Wellcome Dam at Kabete; pond on Nakuru to Eldoret road; Dam at Limuru north-west of Nairobi) (Young 1976b). Morphological notes. Body length up to 2.4mm, extremities rounded, fairly transparent (t.l.), whitish (i.l.). Posterior end with adhesive glands. Semi-rigid bristles singly or in groups of up to 4 along lateral margin; anterior end with very few bristles, 8-13µm long. Rhabdites scattered in groups of up to 8, though mostly 2 to 6, over entire body surface. Rhammite tracks present. Eyes in dorso-posterior position of brain. Excretory system comprised two main coiled stems with branching ducts; external opening were not observed. Body muscle wall structured as usual; dorso-ventral fibres present. Gut with bi-layered muscle sheath. Reproductive system with bilateral testes and ovaries. Female atrium ciliated, cilia 8µm in length; medio-anterior wall of atrium with cellular closure apparatus; sometimes sperm were attached to this. Short, ciliated vagina surrounded by glandular cells. Vasa deferentia join in the region caudal of the gut; the common vas deferens forms a false seminal vesicle which is separated from the seminal vesicle by a slight constriction. Seminal and prostatic vesicle connected by an intervesicular duct. Spiral muscles sheath both the vesicles. Prostatic vesicle with extravesicular glands. Stylet (Plate VI: I) elongated and curved (bow-shaped) in one plane. Length of stylet (d) ranged from µm, averaged 200µm; averaged diameter a = 17µm and e = 4µm. Distal opening oblique and terminal. Walls of distal opening slightly thickened. Macrostomum crenatostylum (Ferguson, 1940) Ferguson 1954 (Plate X: *B; Tab. 1) Synonymy. Macrostomum ruebushi var. crenatostylum Ferguson, 1940; p , fig. 11. Type locality. Neighbourhood of Knoxville, Tennessee, USA, NEA; types: USNM-W, 20445, (paratypes). Habitat. Littoral phytal, spring-fed lakes, freshwater. Geogr. distribution. NEA: USA (Tennessee: Little River at Townsend, Great Smoky National Park) (Ferguson 1940a). Morphological notes. Body length up to 1.3mm by 0.3mm width, with rounded extremities, tail region spatulate with constriction behind last egg. Body colourless except for 79

80 greyish black ovaries and eggs. Rhammite glands absent. Sensory spines and tufts of ciliary hairs space regularly lateral margin; anterior spines, 17µm in length, present. Rhabdites spread over body surface in groups of from 8 to 10. Black eyes present. Epidermis laterally, anterior to testes, massed with spindle-shaped cells (rhammites?) forming two or three strata. Excretory system with lateral convoluted tubules; external pores of the lateral tubules empty just anterior to the testes. Chromosome number n=3. Reproductive system with bilateral testes and ovaries. Gonopores separate. Seminal and prostatic vesicle ciliated interiorly. Seminal vesicle strongly muscularised, prostatic vesicle reduced in musculature. Stylet funnel with almost straight main axis and sharply pointed and bent termination, is 53µm in length (?d) with distal, subterminal opening. The terminal portion is bent at an obtuse angle of α = 115. Sperm cells lack setae. Female genital system normally developed. Fig. 36. Stylets of Macrostomum orthostylum (A, B); stylets of Macrostomum curvatum (C, D), (bars 20µm) (C after Bauchhenss 1971). Macrostomum curvatum Papi, 1951 (Plate IX: B, Fig. 36C-D) Synonymy. Macrostomum orthostylum var. curvata Papi, 1951; p figs Macrostomum orthostylum var. recurva Papi, 1951; legend to figs (lapsus linguae). Type locality. Finland, Europe ; leg. 27. June 1950; types: deposition not recorded. Habitat. Sublittoral, phytal, on Fontinalis antipyretica Hedw., freshwater. Geogr. distribution. EUROPE: Germany (Franconia) (Bauchhenss 1971). Morphological notes. Body length up to 1.5mm, typically macrostomid-shaped, anteriorly rounded and posteriorly spatulate with constriction (waist) at level of male organs. Posterior end surrounded with adhesive glands. Eyes and rhabdites present. Reproductive system with bilateral testes and ovaries. Gonopores separate. Seminal and prostatic vesicle joined by short intervesicular duct. Stylet slightly curved, 61µm long (d). Remarks. Luther (1960, p. 77) and Bauchhenss (1971, p. 621) assumed that Macrostomum orthostylum var. curvatum Papi and Macrostomum orthostylum Braun, 1885 are one and the same species though the stylet of the variety curvata Papi is slightly bent (Plate IX: B, Fig. 36). The argumentation of Bauchhenss is based on the fact that the different forms were living in the same habitats. Luther argued the bend of the stylet was caused by contraction of protractors of the stylet. Deformation of stylets was also reported by Meixner (1915, p. 472) caused by muscular contractions during squeezing under a coverglass. Bauchhenss (1971) ascertained that the proximal opening of straight stylets is relatively greater than that of bent stylets but the length of the straight and bent stylets is identical. Macrostomum curvistylum Ferguson, 1939 (Plate X: *D) Type locality. Milam Gap, Skyline Drive, Appalachian Mountains, Virginia, USA, NEA; types: deposition not recorded. Habitat. Swampy meadow fed by a spring, stygophilic, freshwater. 80

81 Morphological notes. Body length up to 0.73mm by 0.23mm width, terminal rounded, cigar-shaped body gradually reducing at the spatulate tail, colour white (i.l.). Sensory spines of posterior body occupy the region of the adhesive spatulate tail; spines of the anterior end occupy the rounded periphery of the anterior body-end. Hairs, single or in groups, space regularly along lateral margins. Eyes absent. Rhabdites present in epidermis. Excretory system with lateral convoluted stems; external pores of the lateral stems not observed. Reproductive system with bilateral testes and ovaries. Vasa deferentia unite in mid-line just posterior of female atrium to pass into the seminal vesicle; common vas deferens absent. Entrance to seminal vesicle ciliated. Prostatic vesicle without ciliated chambers. Stylet presents an elongate funnel, with distal bend (α > 90 ), gradually tapering, with distal opening produced by oblique truncation; proximal base of stylet crenated. Length of stylet d = 68µm. Female system structured as usual; common oviduct present. Remarks. Schwank (1986) designated M. curvistylum as a true stygobiont species. Macrostomum curvituba Luther, 1947 (Plates IV: I, VI: J; Fig. 82; Tabs 5, 10) Type locality. Near Tvaerminne, Finland, Gulf of Finland, BAL; leg. K. Purasjoki, 11. Aug. 1945; types: deposition not recorded. Habitat. Eu- and sublittoral benthal and stygal, sand, shell gravel, and mud, except saltmarshes, down to 30m water depth, brackish, freshwater. Geogr. distribution. BAL: Gulf of Finland (Tvaerminne, Lakvik, Henriksberg, Kallvassa, Olknäs, Islands: Spikarna, Storlandet, Långskär, Vikarskär, Halsholmen, Brännskär, Segelskär), Sweden (skerry coast off Stockholm: Askö, Södermanland: Endholmen, Tyresö, Korpmarn, Nynäshamn, Torö, Nämndö, Sandhamn, Gotland: Visby, Skåne: Simrishamn, Kattegat: Tylösand), Kieler Bucht (Schlei: Große Breite, Schilksee, Surendorf, Windebyer Noor); ANE: North Sea (North Frisian Islands: Amrum, Sylt; Elbe and Weser river estuary; Faroe Islands: Saksun, Kaldbaksfjord); Skagerrak (Gullmarfjord: Kristineberg, Bohuslän, Bohus Malmön); PNE: Alaska (Kotzebue Sound) (Armonies 1987, 1988, Ax 1951a, 1954, 1956a, 1995a, Ax & Armonies 1990, Ax & Ax 1970, Düren & Ax 1993, Gerlach 1954, Karling 1974, Jaeckel 1962, Jansson 1968, Luther 1960, Müller & Faubel 1993, Rixen 1961, Schmidt 1972b, Sterrer 1965, Westblad 1953). Morphological notes (Plate IV: I). Body length up to 1.5mm, typically macrostomid like, anterior end rounded, posterior end distinctly spatulate with adhesive glands, 5-7µm long. Tactile bristles, single or in tufts, up to 15µm long, around terminal ends; single bristles along lateral sides of body. In t.l. colour transparent with yellowish contrasting gut. Eyes lacking. Rhammite tracks run from latero-ventral region caudal of pharynx in direction to anterior end and mouth; rhammites up to 15µm in length. Rhabdites numerous, either as rhabdites bundles, 10-16µm in length, with 2-6 rods, or as single rhabdites distributed over whole body. Reproductive system with bilateral testes and ovaries. False seminal vesicles (distal parts of vasa deferentia swollen by excess sperm production) communicate with seminal vesicle via common vas deferens. Seminal and prostatic vesicle alled with circular muscle fibres, immediately connected with each other; intervesicular duct absent. Extra-vesicular glands enter prostatic vesicle proximally. Stylet, slightly curved, with thickened wall around distal pore (type of Macrostomum tuba), directed backwards. Measurements of stylet (Plate VI: J): d = 80-98µm, a = 16-18µm, e = 4-5µm; Ax & Armonies (1990, Alaska): d = 89-91µm, a = 12-5µm, e = 4-5µm; Ax (1994, Faroe Islands): d = µm. Female atrium divided into rostral ciliated part and caudal non-ciliated part. Epithelium of rostral atrium with tall cells and enlarged nuclei. Ecological notes. M. curvituba was dominantly found in sandy sediments above and below the coastal groundwater level (Lappvik, Finland, Ax & Ax 1970, Fig. 82), in sublittoral shell 81

82 gravel (Gullmarfjord, Kristineberg, at Bökevik after Westblad 1953), in salt-marhes on muddy substrates (Rixen 1961), in tide pools (2 ind. / 100cm²) on sandy flats covered with thin muddy layers in limnetic areas of the Elbe Estuary near Geesthacht (Müller & Faubel 1993) and in a sandy beach slope of the Elbe river near Harburg (max abundance 32 ind./10cm 2 in April, Düren & Ax 1993). M. curvituba was observed in saltmarshes (Armonies 1987) and abutting supralittoral sandy slopes of lentic areas (Hellwig (1987) of the North Frisian Island Sylt. The species tolerated fluctuations of salinity from 2 up to 20 (Armonies 1987). Sexually mature specimens were found in November, 30 ind./10cm², and February, 4 ind./10cm², and juveniles in February and fall on lentic upper sandy slopes abutting to saltmarshes. In saltmarshes the population dynamic increased to maximum values, 21 ind./ 10cm², between January and May; the distribution, however, was clumpy, 2.2 to 20.8 ind./10cm². Based on the preference of low temperatures and high salinities up to 20 in winter time, offsprings hatched from cysts, grew up and attained sexual maturity. The reproduction phase continued from March to May. The summer months were outlived in low abundance only by juveniles. In experiments M. curvituba preferred low temperatures as they predominate in the localities known to date (Armonies 1987). Autecological characterisation. M. curvituba represents a typical brackish water form and favours low temperatures and oligo- to mesohaline habitats (0.1 8 ). Hatching is favoured by high salinities and low temperatures (Armonies Ax 2008). The favoured low temperatures is evidently the reason that M. curvituba was not recorded southern of the northern latitude of 53 (Ax & Armonies 1990). Food. The species feeds polyphagously on micro-organisms (rotifers, juvenile oligochaetes and turbellarians: Bothriomolus balticus Meixner) and on algae (diatoms, flagellates,green algae: Pediastrum sp.). Macrostomum delphax Marcus, 1946 (Plates IV: H, X: V) Type locality. Rivers Tietê, Pinheiros and Jaguaré, neighbourhood of Limão, district of Sao Paulo, Brazil, leg. Oct., Dec. 1945, Febr., April 1946; types: deposition not recorded. Habitat. Sublittoral benthal, muddy, organic rich sediments, between roots of Trianea bogotensis H. Karst., Heteranthera reniformis Ruiz & Pavon, Eichhornia crassipes (Mart.) Solms, freshwater. Geogr. distribution. NEO: Brazil (Sao Paulo: Butantan) (Marcus 1946). Morphological notes (Plate IV: H). Body length up to 1.8 mm by 0.5mm width, outline of body typically macrostomid-like with spatulate, adhesive, rounded rear end, anterior body end blunt; colour (i.l.) of juveniles white and of adults yellowish grey; parenchyma with pigment granules; brownish pigment present in the epithelium of the pharynx. With rhabdites, eyes, and long bristles along margin and rear body end; anterior margin of body with shorter tactile spines. Rhabdites more numerous laterally and at posterior body end and more numerous dorsally than ventrally. Broad rhammite track between brain and frontal margin,. Ingested food diatoms, green Flagellata, Thecamoeba, Rotifera, Oligochaeta, Crustacea and others. Reproductive system with bilateral testes and ovaries. Distal end of stylet spiralled (Plate X: Va); strong squeezing may open the spiral (Plate X: Vb); distal opening of stylet subterminal. Length of stylet ca. 120µm, distal spiral end 30 to 40µm in diameter. Diameter of proximal opening a = 40µm. Gonopores separate. Female antrum entered by cement glands, connected to female atrium via short ciliated vagina. Female atrium ciliated with the exception of the proximal third. Transition from female atrium to common oviduct provided with closure-apparatus. Haploid number of chromosomes of sperm n = 2. 82

83 Macrostomum deltanensis Beltagi & El-Said, 2002 (Plate VI: K) Type locality. Freshwater pond near El-Halaby Village, Nile Delta, Egypt, NAF; leg. S. Beltagi; types: DZASU-C. Habitat. Phytal of Elodea canadensis L.C. Rich. in Michx., Eichhornia crassipes (Mart.), freshwater. Morphological notes. Body length up to 2mm, oval in shape with broadly rounded anterior and spatulate posterior end, maximum width at level of first body-fourth, pale white in i.l. Sensory hairs and spines absent. Adhesive papillae at ventral rim of last body-fourth. Brownish black eyes paired, and rhammite tracks present. Brain gives rise to 4 pairs of nerve stems as following: anterior nerve stems, antero-lateral nerve stems, lateral nerve stems, and postero-ventral nerve stems. Rhabdites in bundles, each 6 to 8µm in length; rhabdites dorsally more abundant than ventrally. Epidermis with intra-epithelial nuclei and with adenal and epithelial mucous glands. Body muscle wall structured as usual; dorso-ventral muscle fibres present in parenchymatous parts of body, especially in the anterior and posterior body parts; diagonal muscle fibres extend through the whole parenchymatous tissue. Protonephria not found. Intestine walled with strong outer longitudinal and inner circular muscle layers; inner intestinal margin distinctly indented. Predator on copepods, Cypris larvae, rotifers, and others. Reproductive system with bilateral testes, alongside of intestine in anterior part of body, and ventral ovaries. Gonopores separate. Distally, vasa deferentia expanded to false seminal vesicles, join to common vas deferens; common vas deferens enters proximally the muscular seminal vesicle. Short intervesicular duct present. Prostatic vesicle surrounded with numerous extravesicular glands which pour their prostatic contents into the distal part of the prostatic vesicle. The proximal part of the prostatic vesicle is broad and internally ciliated. The distal part of the prostate tapers to a small duct which passes over into the proximal part of the stylet. The stylet distad slightly tapering, is a double-curved tube (S-shaped; evidently flexed in more than one plane) directed backwards ventro-caudad (Plate VI: K). Distal part of stylet with tuba-like thickening. Length of stylet 321µm (a = 26µm, e = 18µm). Macrostomum distinguendum Papi, 1951 (Plates IV: G; V: M; Tabs 4, 10) Synonymy. Macrostoma hystrix: v. Graff 1882; p. 241, pl. IV: fig. 9, 12 (pro parte). Macrostomum appendiculatum distinguenda Papi, 1951; p , fig. 38. Macrostomum rossicum Beklemischev, 1951; p , figs 19, Macrostomum hystricinum: Chodorowsky 1959; p , phot. 2. Type locality. River Myllyoja, Kittilä, Finland, Europe, leg. July 1950; types: deposition not recorded. Habitat. Sublittoral benthal, preferably sand or sandy mud, phytal of Callitriche palustris L., Hydrocaris sp., Agrostis stolonifera L. in Phragmites belt, swamps, helokrenes, ponds, pools, puddles, ditches, fluviatile and stagnant waterbodies, freshwater. Geogr. distribution. EUROPE: Austria (Danube and tributary streams), England (North Wales, Western Midlands: lowland calcium-rich lakes, Lancashire), Faroe Islands: Sound between Streymoy and Esturoy near Hósvik; Finland (Kittilä, Sirkka, Janakkala, Myllyoja, Puujoki, Vääksy), Germany (Lower Saxonia: Seeburger See, region around Göttingen; Schleswig-Holstein; Hamburg-Harburg: Elbe River; Thuringia: Jena, Mühlhausen, Schlotheim; Franconia, Danube, Schwarzwald: Falkau, Bodensee), Italy (Pisa: forest of S. Rossore), Poland (Harsz Lake, Lake Zbęchy), Romania (Danube estuary: predeltaic region the melea St. George, Filipoiu-Canal: Brăila-Balta; near Mureşului), Russia (RU-W: St. Petersburg, RU-C: Sudimir, Kaluga, RU-E: Perm), The Netherlands (freshwater of inner Scheldt, Wijde Ee Lake, De Veenhoop, Oorden Lake, Ameland); EPA: Siberia (Tomsk) (An 83

84 Der Lan 1962, 1967, Ax 1995a, 2008, Bauchhenss 1971, Den Hartog 1977, Düren & Ax 1993, Heitkamp 1981, Heitkamp et al. 1985, Kaiser 1967, 1974, Kolasa 1979, Luther 1960, Mack-Firă 1968b, c, 1974, Papi 1951b, Pörner 1966, Rixen 1961, 1968, Tulp 1974, Young 1970, 1972c, 1973). Morphological notes (Plate IV: G). Body length up to 1.4 mm, macrostomid-shaped with rounded anterior end and spatulate, bluntly rounded posterior end surrounded with adhesive glands. Colourless, digestive system contrasts yellow or greenish due to ingested diatoms and/or Chlorophyceae. Predation on Thecamoeba were reported by Rixen (1961) Black eyes in dorso-posterior position of brain. Sensory bristles, often in pairs, spaces lateral margin, up to 40µm long; tactile bristles around frontal margin 13µm long. Rhammite tracks extend to frontal margin. Bundles of adenal rhabdites, 5-12µm in length, distributed dorsally (more abundant) and ventrally. Body muscle wall structured as usual. Pharyngeal glands intensively developed. Reproductive system with bilateral testes and ovaries. Gonopores separate. Seminal vesicle with proximal duct walled with circular muscle fibres. Intervesicular duct absent. Stylet (Plate V: M) curved, funnel-like, with distal pore subterminal on the convex side; measurements after Luther (1960): d = 70-78µm (Lapland specimen d = 70), a = 19-24µm (Lapland specimen 19µm), e = 12-13µm; Rixen (1961): d = 55-85µm, a = 25-40µm, e = 6-12µm; Bauchhenss (1971): d = µm, a = 12-43µm, e = 6-15µm; Ax (2008): d = µm, a = 30µm, e = 8µm. Female system composed as usual. Female atrium distally ciliated; rostral closure-cells not observed at transition to oviduct. Ecological notes. Maximum abundance from May to September: ind./m² (Heitkamp 1982), occurrence from March to October: 4-25 C (Bauchhenss 1971). M. distinguendum undergoes a polyvoltine life cycle with 1 5 generations per year (Tab. 10). Specimens developing eggs, were observed from March to Ocrober. Autecological characterisation. Eurythermic, water velocity: oligo- to mesorheoplastic; temperature, oxygen, and ph: γ-oligo- to mesoplastic, calcareous content and substrate: euyplastic (Heitkamp 1982). Food. Just as M. rostratum, M. distinguendum feeds pantophagously on Chlorophyceae (diatoms, Chlorophyceae: Chlorella sp. etc.) and Thecamoeba, Ciliata, Rotifera, and offsprings of Turbellaria (Heitkamp 1982). Remarks. As Luther (1960, p. 74) has been annotated, the species is evidently distributed in whole Europe but often taxonomically determined as Macrostomum appendiculatum or M. hystrix. Macrostomum dorsiforum Beltagi, 1972 Type locality. Shebin El Kanater, 25km far from Cairo, Egypt, Africa; leg. July to Aug. 1969; types: private collection. Habitat. Sublittoral phytal, Eichhornia spp., Elodea spp., Ceratophyllum spp., Potamogeton spp., freshwater. Morphological notes. Body length up to 3.0mm, typically macrostomid-like, anteriorly broadly pointed, posteriorly truncated with adhesive glands; posterior end waisted caudal of gut to form a spatulate tail. Colour transparent (t.l.), with digestive system contrasting pale grey. Eyes dark brown. Epidermis with adenal glands and intra-epithelial nuclei the exception being the spatulate tail where they are depressed. Rhammite tracks present, the glands of which lie caudo-lateral of pharynx. Adenal rhabdites distributed over the whole body with greater abundancy at the extremities. Mouth and pharynx simplex entered by pharyngeal glands; intestine ciliated, lined with cylindrical cells and walled with bi-layered muscle sheath. Minotian cells present. Excretory system not observed. 84

85 Reproductive system with bilateral testes and ovaries. Vasa deferentia unite to common vas deferens which proximally dilates to form a false seminal vesicle. The distal vas deferens pass into the strongly muscularised seminal vesicle. Intervesicular duct present. Prostatic vesicle with extravesicular glands arranged around the proximal half of the vesicle. Stylet a long undulated tube, with length of about 378µm; tube proximally straight, medially twisted, and distally slightly bent. Female system composed as usual. Oviducts with bi-layered muscle wall, unite medially to a short common oviduct which enter the female atrium via the closureapparatus. Beltagi (1972, p. 358) interpreted a group of large non-ciliated cells at the posterior part of the female atrium as a transitional stage which leads to the formation of the ductus genito-intestinalis. Gonopores separate. Macrostomum elgonensis de Beauchamp, 1936 (Plate X: G) Synonymy. Macrostomum viride var. elgonense de Beauchamp, 1936 ; p , fig. 4. Macrostomum beauchampi Ferguson, 1939; p , fig. 9. Type locality. River Swan, Mt. Elgon, altitude up to 4000m, Uganda, Africa, leg. 7. Jan. 1933; types: deposition not recorded. Habitat. Littoral phytal, mosses, freshwater, T = 12 C. Morphological notes. Body length up to 2.0 mm, shape of M. appendiculatum, anterior end blunt, posterior end spatulate. Eyes in front of pharynx. Rhabdites in bundles, distributed over body-surface. Pharynx long. Reproductive system with bilateral testes and ovaries. Seminal vesicle elongate joined via intervesicular duct with bulbar prostatic vesicle encased by proximal stylet. Stylet an extended slender funnel, straight with helicoidal distal termination, the opening of which terminal at oblique truncation; length of stylet 0.55mm (Plate X: G). Female system not mentioned. Macrostomum ensiferum Beklemishev, 1951 (Plate IX: E) Type locality. Lenkoran, Caspian Sea, EPA; leg. 12 July 1914; types: deposition not recorded. Habitat. Sublittoral seagrass belt, brackish. Morphological notes. Body length up to 1.5mm, macrostomid-shaped, extremities rounded, posterior end disk-like tail with waist at level of male organs, colourless translucent (t.l.). Rear body end with adhesive glands, rhabdites, and spines. Rhammite tracks hardly to recognise. Eyes black. Pharynx simplex smaller than in other species. Gut dark yellow. Reproductive system with bilateral testes and ovaries. Stylet (Plate IX: E) slightly curved tube tapering distad with apical opening. Macrostomum ermini Ax, 1959 (Plates IV: L; VI: L) Type locality. Sile, Black Sea, MED; leg. Sept. 1956; types: deposition not recorded. Habitat. Supralittoral pool, benthal, fine to medium sand with low fraction of detritus, salinity varied between 14.5 to 17.9, mesohalinicum. Morphological notes (Plate IV: L). Body length up to 1.2mm, typical macrostomid outline with spatulate tail region, extremities rounded, posteriorly more blunt. Rear body end with adhesive glands. In t.l. colour light yellow. Brownish black eyes anterior to pharynx. 85

86 Rhammite tracks open at frontal margin. Groups of rhabdites scarcely distributed over the body surface. Reproductive system with bilateral testes and ovaries. False seminal vesicle present. Seminal and prostatic vesicle joined by a short intervesicular duct. Prostatic vesicle with extravesicular glands producing only one type of spindle-shaped secretion. Distal part of prostatic vesicle not encased by proximal base of stylet. Stylet (Plate VI: L) an elongate tube, slightly curved and gradually tapering distad. Length of stylet varies between the extremities from 132 to 164µm. Distal end slightly expanded with solid hook; wall across from hook bulbar-like thickened; distal opening obviously between hook and bulbar thickening. Female system composed as usual. Female atrium distally ciliated; dorsal lining of medium part sclerotised and folded; rostral part with tall epithelial lining forming the closure apparatus to the oviduct. Gonopores separate. Macrostomum extraculum Ax & Armonies, 1990 (Plate VI: E) Type locality. Lagoon near Cook Inlet River, Ninilchik, Kenai Peninsula, Alaska, PNE; leg. Ax, 17. June 1988; types: not prepared. Habitat. Eulittoral benthal, medium sand mixed with detritus, salinity 5, oligohalinicum. Morphological notes. Body length up to 1.2mm, colourless. Strong bundles of rhabdites and bilateral eyes present. Reproductive system with bilateral testes and ovaries. Intervesicular duct enter in common with extravesicular prostatic glands the prostatic vesicle. Stylet (Plate VI: E) tube-shaped, distally corksrew-like, with proximal funnel, a = 18 to 22µm, and with length from 68 to 72µm. Distal tip of stylet with solid conical enlargement of about 4 x 6µm, subterminal opening e = 3µm. Stylet like a cork-screw, not flexed in one plane. Macrostomum fergussoni Beklemishev, 1951 (Plate X: N; Tab. 1) Synonyms. Macrostomum appendiculatum (Fabricius, 1826) sensu Beklemishev 1922; p. 19. Macrostomum appendiculatum (Fabricius, 1826) sensu Ferguson 1939; p , figs1-5, 7. Type locality. Orenburg, Russia, RU-E; leg.? Tschkalova, types: deposition not recorded. Habitat. Phytal of littoral belt, within tufts of Nuphar sp., freshwater. Geogr. distribution. EUROPE: Poland (Lake Zbęchy), RU-S (Orenburg: Osero Stariza); NRE: Azerbaijan (Chalov), EPA: Japan (Beklemishev 1951, Kolasa 1979). Morphological notes. Morphological charakters looked like M. hystricinum. Reproductive system with bilateral testes and ovaries. Stylet (Plate X: N) length 59.8µm, spirally S-shaped in one level, opening subdistal, basally obliquely cut with pleated margin. Remarks. The synonymy of Macrostomum appendiculatum sensu Ferguson and M. appendiculatum sensu Beklemishev is evidently not justified because the distal openings of the stylets are distinctly different. The distal opening of the stylet of the American species is at the distal bend (Fergusson 1939a) and the opening of the Russian species is just subterminal of the tip. In addition, the outline of both the stylets looks different. Beklemishev (1951) justified the establishment of Macrostomum fergussoni both on the different position of the distal openings and on the basis of the geographic isolation of the species. Furthermore, Beklemishev pointed to evidently inaccurately prepared drawings. Macrostomum finnlandensis Ferguson, 1940 (Plate X: *L; Tabs 1, 4, 10) 86

87 Synonymy. Macrostomum viride Van Beneden, 1870 sensu Luther 1905; p. 4-48, fig. 3, pl. I: figs 1, 9, 11, pl. II: figs 2, 9, pl. III: fig. 9, Pl. IV: figs 8-11, 23-25, 29, Macrostomum appendiculatum: Schultze 1851; p , plate V: fig. 3. Macrostomum viriede: Beklemishev 1922; p. 19 (lapsus linguae). Macrostomum ruebushi var. finnlandensis Ferguson, 1940; p , figs Macrostomum appendiculatum finlandensis: Luther 1947; p , figs Macrostomum finlandense: Luther 1960; p. 72. Type locality. Lohjanjärvi, Kirchspiel Lojobacken, south of Finland, Europe; leg. A. Luther, June to July 1901; types: deposition not recorded. Habitat. Littoral phytal and benthal, Potamogeton sp., swamps, muddy sediments, freshwater. Geogr. distribution. EUROPE: Finland (Kittilä: Sorettianjärvi, Sirkka; Luusa: Immeljärvi, Janakkala, Rauhaniemi, Puujoki, Lohjanjärvi, Tytyri, Lill-Ojamo, Lappvik (harbour), Ekenäs, Tvaerminne, Gloet, Esbo Bodom träsk), Germany (Franconia), Italy, The Netherlands (Oude Maas), Poland Lake Zbęchy), (Romania (Danube estuary: Lacul Snagov; Bucharest), RU-E (Saratov); EPA: Siberia (Tomsk) (Bauchhenss 1971, Den Hartog 1977, Kolasa 1979, Luther 1947, 1960, Mack-Firă 1968c, Nasonov 1924, Nasonov 1919b). Morphological notes (after Ferguson 1940a and Luther 1947). Body with rounded extremities, tail region spatulate. Body colourless except for the yellow-green gut due to algae ingested. Rhammite glands are around mouth opening. Rhabdites spread over body surface being more numerous at the posterior end. Sensory spines space regularly the lateral margin; anterior and posterior spines densier and longer. Large, reniform eyes present. Chromosome number n = 3. Reproductive system with bilateral testes and ovaries. Gonopores separate. Vasa deferentia unite to common vas deferens which forms a false seminal vesicle if excess sperm production occurs. Seminal and prostatic vesicle joined by a very short intervesicular duct. Stylet 135µm in length (d = 148µm) with distal, subterminal opening. Main axis of the stylet not in one plane. Stylets lost their spiral outline if specimens will be stronger squeezed, i.e. flattened under the increasing pressure of the coverslip (cf. Luther 1947, figs 7-9). Female genital system composed usual. Remarks. Ferguson (1940a, p ) established for Macrostomum viride sensu Luther 1905 the new name Macrostomum ruebushi var. finnlandensis. Based on the very diffuse description of Macrostomum viride Van Beneden, 1870, taxonomical determinations of the species were mistaken by several authors for M. hystrix Oersted and M. appendiculatum Fabricius later on. Therefore, Luther (1947, p ) was convinced that many European species designated Macrostomum viride Van Beneden, M. appendiculatum Fabricius or M. hystrix Oersted, would resolve into several well described species, respectively subspecies when they would be studied again (Luther 1960) (for comparison see also the remarks made for M. hystricinum Beklemishev, 1951, p. 17). In several studies on Macrostomum finnlandensis, different measurements of the length of the stylet were given as following: Papi 1951b: 80µm, Rixen 1961: 55-66µm, Bauchhenss 1971: 59-73µm, Heitkamp 1979: 55µm, a = 15µm, e = 5µm. The measurements prove a wide range of the length of the stylets. The question arises, is the stylet length depending on environmental conditions or there are hidden different species within this species complex or are the measurements made, related to different stages of develpment? Ecological notes. M. finnlandensis was sampled in Franconia (Bauchhenss 1971) in April and from August to October (T = C). Animals producing eggs, were observed in September. Heitkamp (1982) collected a single specimen in May 1975; he calculated 2-3 generations per year (Tab. 10). 87

88 Autecological characterisation (Heitkamp 1982). Thermophilous, rheophobous, oligo- to mesotitanoplastic, substrate: polyplastic; phytophilous. Food. Green algae, detritus, grains of pollen, Rotifera (Heitkamp 1982, Bauchhenss 1971, Schwank 1980). Fig. 37. Macrostomum flexum. A. and B. Stylets of different speci-mens of Jusan Lake; distal end of stylet amplified, adjacent to stylet (after Ax 2008). Macrostomum flexum Ax, 2008 (Plate VIII: I, Fig. 37A-B) Type locality. Jusan Lake, Honshu, Aomori District, Japan Sea, PNW; leg. Prof. Dr. Ax, Aug. to Sept. 1990; types: deposition not recorded. Habitat. Benthal, sandy beach, consolidated sandy bottom between roots of Phragmites belt, salinity range from 28 to freshwater, holeuryhaline. Morphological notes. Body length up to 0.5mm; transparent colourless, with intestine taking on yellowish colouration when diatoms ingested, eyes present. Reproductive system. Slightly curved stylet of tuba type (Fig. 37) with faint funnel-like proximal opening; distally, opening of the stylet annularly thickened; d = 51-60µm, a = 12 17µm, e = 4 5µm. Remarks. The stylets of Macrostomum flexum and M. rectum agree largely with each other. Due to the fact that morphological notes on M. rectum are absent, Ax (2008) keeps both the species for the present as true valid species based on the great geographic isolation of the type localities and their different habitats. Macrostomum frigorophilum (Ferguson, 1940) Ferguson 1954 (Plate X: E) Synonymy. Macrostomum ruebushi var. frigorophilum Ferguson, 1940; p , figs Type locality. Spring, Rockbridge County, Virginia, USA; types: deposition not recorded. Habitat. Krenal, phytal, on Spirogyra sp., freshwater. Morphological notes. Body length up to 1.6mm by 0.4mm width, macrostomid-like in shape, anterior end not so abruptly truncated as the posterior end; rear end with function of adhesion but without a pronounced disk. Body colourless. Unusual, numerous rhabdites, in groups of 7 and 8, spread over body surface. Ciliary tufts in groups of two or three, up to 5µm long, space regularly the lateral margin; anterior and posterior tufts densier and shorter, up to 2µm long. Cilia over the body 1.3µm long. Large eyes made up of a pigmented cup supplied with a hyaline lens-like region connected to the caudal tissue of brain by a slender neutral stalk. Excretory system with two main lateral stems; openings to the exterior not determined. Mouth guarded by ciliary lips, unusual long, and fewer than the normal number of mucous glands surrounding it Reproductive system with bilateral testes and ovaries. Vasa deferentia unite to a short common vas deferens which depending on sexual maturity, could distend to a false seminal vesicle. Intervesicular duct absent. Prostatic vesicle with characteristic ciliated chambers. Stylet (Plate X: E) 88µm in length with pointed distal end at an angle of almost 90 ; distal 88

89 opening e = 2.7µm. Sperm cell with lateral setae. Female genital system composed as usual. Female atrium ciliated, with rostal sphincter to common oviduct. Gonopores separate. Macrostomum gabriellae Marcus, 1949 (Plate V: F; Tab. 1) Type locality. São Vicente, Ilha das Palmas, Bay of Santos, Brazil, ASW, leg. Dr. D. Gabriella P. Zuccari, 1948; types: unknown. Habitat. Eulittoral fringe of sandy beaches, on Ulva spp. and other algae, marine. Morphological notes. Body length up to 0.6mm by a maximum width of 0.08mm, fore-end and caudal end of body rounded but caudal end somewhat spatulated; adhesive glands around spatulated tail; colourless. Rigid bristles space irregularly along margin, anteriorly and posteriorly at spatulate region more dense. Large eyes, 12µm in length, and adenal rhabdites present. Rhammite tracks piercing brain, open at frontal margin. Anterior part of intestine with Minotian cells; ciliated lining present. Specimens feed on diatoms. Haploid number of chromosomes n = 3. Reproductive system with separate gonopores. Distal part of prostatic vesicle encased by proximal part of stylet. Stylet (Plate V: F) bent backwards, proximally broad, funnel-shaped; distal opening, e = 4µm, at bend of main axis, 14µm distant from point of stylet; length of stylet from distal opening to proximal basis 30µm. Female apparatus consists of distal vagina, atrium, and common oviduct; entrance of oviduct into the rostral atrium is marked by higher cells (cellular closure apparatus). Remarks. The description of the genital organs made by Marcus (1949), is very meagre as to the anatomy of the prostatic vesicle. According to the drawing (Marcus 1949, Fig. 20), the prostatic vesicle encased by the proximal part of the stylet, seems to be reduced and extravesicular glands surround the stylet. That implies Macrostomum gabriellae has to remove to the genus Archimacrostomum. However, I desist from that emendation because the anatomical informations given by Marcus are too scanty. Macrostomum gallicum Ax, 2008 (Plate VI: R; Fig. 38) Type locality. Courant de Lége, Bassin d Arcachon, France, ANE; leg. Prof. Dr. Ax, 1964; types: deposition not recorded. Habitat. Eulittoral benthal, mud to clay grown with Cyanobacteria, limit range between oligohaline and freshwaters. Fig. 38. Macrostomum gallicum. Male copulatory apparatus. After Ax distal opening of the stylet thickened; d = 65µm. Morphological notes. Body slender with length up to 0.7mm; body end with adhesive plate; eyes present; uncoloured. Reproductive system. Male copulatory apparatus with seminal and prostatic vesicle joined by a short intervesicular duct. Prostatic vesicle with extravesicular glands; prostate not encased in proximal stylet. Curved stylet of tuba type (Fig. 38); 89

90 Macrostomum galloprovinciale Schmidt & Sopott-Ehlers, 1976 (Plates IV: D; VI: M) Type locality. Bahía Academy, Santa Cruz, Galapagos Islands, PSE; leg. Schmidt, Febr to March 1973; types: only life observations on two specimens. Habitat. Eulittoral benthal, heterogenous sandy sediments, marine. Morphological notes (Plate IV: D). Body length up to 0.4mm by 0.1mm width, typically macrostomid-shaped, anteriorly broadly rounded, posteriorly spatulate tail with rounded end, colourless to weakly grey (t.l.). Anterior and posterior end with rigid tactile cilia up to 10µm long. Caudal rim of spatulate tail occupied at least with 60 adhesive glands, each about 3-4µm long. Adenal rhabdites, in groups of 8 to 12, distributed over the body surface, most abundant in region of spatulate tail. Rhammite tracks run to the anterior margin and to the mouth opening from caudal regions of the pharynx. Bilateral reniform eyes at posterior border of brain. Specimens feed on diatoms. Reproductive system with bilateral ovaries and probably bilateral testes. Specimens evidently not in full sexual maturity. Seminal vesicle, small, and prostatic vesicle present. Interior of prostate with two spheroidal strands of granules passing into the proximal part of the stylet. Stylet (Plate VI: M) 30µm in length, slightly curved; distal end with ring-like, uneven thickening. Female system incompletely developed. Macrostomum georgeensis Young, 1976 (Plate X: Q) Type locality. Lagoon where River Nsonge enters Lake George, Uganda, ETR; leg. 16. April 1972; types: BMNH-L, Habitat. Sublittoral phytal, freshwater. Morphological notes. Body length up to 1.0mm, posterior and anterior ends somewhat truncated, narrowing posteriorly to spatulate tail, colourless (t.l.), whitish (i.l.). Posterior end with adhesive glands. Semi-rigid bristles single or in groups of up to 4 distributed sparsely over body surface; length of bristles up to 20µm. Rhabdites, up to 17µm long, sparingly scattered over entire body surface in groups of up to 8, most commonly 2 to 4, without greater concentration. Rhammite tracks present but inconspicuous. Eyes in dorso-posterior position of brain. Reproductive system with bilateral testes and ovaries. Female system as usual. Closure apparaus present but poorly developed. Short vagina surrounded by cement glands. False seminal vesicle obviously absent. Seminal and prostatic vesicle joined by a short but distinct intervesicular duct. Extravesicular prostatic glands absent. Stylet (Plate X: Q) with slight bend proximally and sharp bend distally. Distal opening terminal. Walls of the tube of uniform thickness. Measurements: length from proximal opening to base or lower margin of distal arc 70µm (not corresponding d), a = 9µm, e = 3.5µm. Macrostomum gilberti Ferguson, 1939 (Plate IX: C; Tab. 2) Type locality. Whittle springs community, Knox County, Tennessee, USA, NEA; types: USNM-W, Habitat. Krenal, rhitral, freshwater. Geogr. distribution. NEA: USA (Ontario: Point Pelee) (Gregory, Hebert & Kolasa 2000). Morphological notes. Body length up to 1.0mm, typically macrostomid-like with extended truncated tail region, anteriorly broadly rounded, colourless, with intestine taking on colour of food content. Large number of finely granulated cells in the cephalic epidermis. Rhabdites in 90

91 packets of 2, 4 and 8. Spines space irregularly at extremities and ciliary tufts along lateral margins; spines more dense at extremities of body. Reniform eyes located caudal of brain, not embedded in tissue of brain. Protonephridia with bilateral stems, excretory pore of which not found. Reproductive system with bilateral testes and ovaries. Prostatic vesicle with four ciliated chambers. Stylet (Plate IX: C), 72µm long, a curved funnel with widened proximal base to end in a slightly bent obliquely truncated distal tip; distal termination distinctly provided with a thin lip projecting slightly beyond the opening proper. Degree of curving in the tube of the stylet never as much as 90, i.e. > 90. Proximal base of stylet with high degree of coarse crenation. Female system incompletely developed or diagnosed. Gonopores separate. Fig. 39. Macrostomum gohari Beltagi, Ibrahim & Mostafa. Dorsal view of living specimen (after Beltagi, Ibrahim & Mostafa 2000). Macrostomum gohari Beltagi, Ibrahim & Mostafa, 2000 (Fig. 39) Synonymy. Macrostomum goharii Beltagi, Ibrahim & Mostafa, 2000; p. 591, figs Type locality. Ismailia Canal, River Nile near Cairo, Egypt, NAF; leg. Dec to Nov. 1992; types: deposition not recorded. Habitat. Phytal, Elodea canadiensis L.C. Rich. in Michx, floating Eichhornia crassipes (Mart.) Solms, freshwater. Morphological notes. Body length up to 2.0mm by 0.7mm width, outline Macrostomum tuba-like (Fig. 39) with rounded cephalic region, widened mid-body and caudal of gut waisted to form a broad truncated body-end occupied with adhesive glands. Sensory hairs and spines absent. Brownish black eyes kidneyshaped, dorso-posterior of brain, not embedded in tissue of brain. The brain give rise to four pairs of nerve stems. Colour pale yellowish. Epidermis with intraepithelial nuclei and subepithelial mucous glands, in particular ventrally, which open to the exterior by tubular gland necks. Body muscle wall structured as usual; dorso-ventral muscle fibres present in parenchymatous parts of body. Rhammite tracks present. Adenal rhabdites being in packets of 2, 3, 4, 6 or 8 rods, in large numbers in anterior body and along lateral margin. Digestive tract developed as usual. Food particles were small crustaceans. Reproductive system with bilateral testes and ovaries. From each ovary an oviduct runs medio-ventrally and join to a common oviduct. The passage cells of the closure apparatus are pyramidal, located at the anterior part of the female atrium. Female atrium spherical in shape, the walls of which ciliated and made up of cuboical cells. The female atrium passes distally into a ciliated vagina with ventral opening. Bilateral testes fields extend caudad from level of mouth. Distally, each testis passes into a vas deferens which join to a common vas deferens 91

92 extending to a false seminal vesicle. The male copulatory apparatus consists of seminal vesicle, prostatic vesicle and distal sclerotised stylet (Fig. 39). Seminal and prostatic vesicle are connected by a short muscularised intervesicular duct. Seminal vesicle with inner circular and outer longitudinal muscle layer; syncytial lining with intraepithelial nuclei. The prostatic vesicle is only distally filled with fine granules of cyanophilic type. Proximally, the vesicle is divided into 6 interciliary chambers the cilia of which are strong and tall. Extravesicular glands enter the distal part of the vesicle. The vesicle joins distally to a long tubular stylet and penial canal in which the stylet is embedded. The stylet is up to 220µm long (d), slightly bend, and proximally bulbous shaped with an opening a = 45-50µm; distally, the opening is oblique and e = 10-12µm. Macrostomum gracile Pereyaslawzewa, 1893 (Plate VII: A) Synonymy. Macrostomum gracile: von Graff 1905; p , pl. II: fig. 2. Macrostomum graffi Ferguson, 1939; p , fig. 22. Type locality. Sevastopol, Black Sea, MED; types: unknown. Habitat. Littoral benthal, sandy beaches, marine. Geogr. distribution. EUROPE: Portugal (Albufeira) (Gieysztor 1931). Morphological notes. Body length somewhat more than 1.0mm, macrostomid-like outline with rounded cephalic region, widened mid-body and spatulate end occupied with adhesive glands. Black eyes located caudal of brain, not embedded in tissue of brain. Colourless, with intestine taking on yellowish colouration when diatoms ingested. Rhabdites in packets between 3 to 7, rarely packets with up to 15 rods, each of which 6µ in length. Rigid, longer spines space irregularly from anterior margin caudad to level of pharynx. Reproductive system with bilateral testes and ovaries. Vasa deferentia distend distally to false seminal vesicles before passing into seminal vesicle. Prostatic vesicle with extravesicular glands. Stylet (Plate VII: A) 56µm long, more or less straight or very slightly curved, distal part bent; distal tip bluntly truncated with subterminal opening on the convexity of the bend. According to the reproduction given by Luther (1905, plate II: Fig. 2), the distal opening seems to be located subterminally on the concavity of the bend and not on the convexity of the bend as stated in the text. Remarks. Von Graff (1905, p. 81) was convinced having recovered Macrostomum gracile Pereyaslawzewa in beaches off the monastery of St. George, Sevastopol (type locality), and presented an excellent re-description on which the species is recognisable in contrast to the meagre description made by Pereyaslawzewa (1893, p. 243). Gieysztor (1931) collected in canals near rice-fields in the neigbourhood of Albufeira, Portugal, specimens which he determined as Macrostomum gracile Pereyaslawzewa based on the re-description made by v. Graff The lengths of the stylets varied from 50 to 130µm. Ferguson (1939b, p ) erroneously emended Macrostomum gracile Pereyaslawzewa to Macrostomum graffi Ferguson, That error was based on the fact that Ferguson (1939b, p , figs 20-21) confused Macrostomum gracile Pereyaslawzewa with Macrostomum megalogastricum Pereyaslawzewa, Macrostomum granulophorum (Ferguson, 1940) Ferguson 1954 (Plate X: C; Tab. 1) Synonymy. Macrostomum ruebushi var. granulophorum Ferguson, 1940; p , figs Type locality. Yale Game Preserve, New Haven, Connecticut, USA, NEA; type: USNM- W, Habitat. Freshwater. 92

93 Morphological notes. Body length up to 1.0mm by 0.4mm width, outline macrostomidshaped but lacks a definite tail region, anteriorly rounded and posteriorly truncated; broadened in both anterior and posterior regions with a slightly narrowed mid-body region, colourless except for the occurrence of quite numerous granular cells distributed in the epidermis (cf. Macrostomum truncatum Ferguson, 1940). These are light brown in colour, often bilobed, and each measure 51µm in diameter. Adenal rhabdites present. Few ciliary tufts space irregularly lateral margin. Reniform eyes posterior of brain, not embedded in tissue of brain. Excretory system with two main lateral stems supplied with flame cells at their termination; opening to the exterior not observed. Chromosome number n = 3. Reproductive system with bilateral testes and ovaries. Common vas deferens absent. Prostatic vesicle with ciliated chambers. Stylet (Plate X: C) irregularly reduced funnel terminating distally in a pointed end hooked at an angle of about 90 ; its base crenated and distal opening subterminal; length of stylet averaged 99µm. Sperms with two setae. Female genital system composed as usual. Common oviduct present. Walls of female atrium heavily ciliated. Gonopores separate. Macrostomum greenwoodi Faubel & Cameron, 2001 (Plates IV: C, VI: O) Type locality. Coomera salt-marsh, S, E, Gold Coast, Queensland, Australia; leg. B. Cameron, April 1998; types: QM-B G Habitat. Epilittoral salt-marsh pools, bordered by Sporobolus virginicus (Kunth.) and Sarcocornia quinqueflora (ex. Ung. Stern), mud mixed with negligable sand, polyhalinicum, euhalinicum. Morphological notes (Plate IV: C). Body length up to 1.3mm by 0.18mm width, macrostomid-like with waists behind brain and at level of male organs, anterior end bluntly rounded, posterior end not typically spatulated, rounded with tendency to a pointed rear end; pointed rear end carries long ciliary tuft. Caudal end with adhesive glands. Rhabdites evenly distributed in serial lines over ventral and dorsal body. Weak marginal spines of varying length and stiffness present; ciliary tufts absent. Rhammite tracks present, the glands of which lie anterior to level of pharynx simplex. Eyes black, positioned behind posterior border of crescentic brain. In i.l. colour brownish with contrasting darker oocytes in posterior part of body; gut intensively yellow based on uptake and consumption of diatoms. Epidermis with intra-epithelial nuclei and adenal rhabdites; basal membrane not observed, probably absent. Pharynx with extrapharyngeal glands; intestine with less numerous cilia than pharynx. Specimens feed on diatoms and detritus. Reproductive system with bilateral testes and ovaries. Vasa deferentia join to common vas deferens on the right side before entering seminal vesicle. Intervesicular duct present. Distal prostatic vesicle encased in proximal portion of stylet. Stylet (Plate VI: O) slightly bowshaped in one plane with thickended proximal base, measures d = 98.3µm; proximal diameter a = 12.0µm. Distal tip of stylet edgeless, thickened walls, and with subterminal oblique opening. Female system with short ciliated vagina passing into female atrium surrounded with elongated cells; cilia absent. The proper epithelium of the female atrium looks syncytially into which the surrounding cells excrete obviously granulated material. Rostro-ventrally, common oviduct emanates from atrium; special cellular closure apparatus absent. Gonopores separate. Macrostomum guttulatum Ax, 2008 (Plate VI: P; Fig. 40) 93

94 Type locality. Noheji River, about 250m far from opening into Mutsu Bay, Aomori District, Honshu, Japan, PNW; leg. Prof. Dr. Ax, Aug. and Sept. 1990; types: deposition not recorded. Habitat. Benthal, coarse sand mixed with gravel, sandy bottom within Phragmites belt, salinity 5-10 ; supralittoral saltmarshes; mesohaline. Other specimens. PNW: Japan (Aomori District: Jusan Lake,salinity 5 ; Obuchi Pond in saltmarshes, north of Ogawara Lake) (Ax 2008). Fig. 40. Macrostomum guttulatum. A. Male copulatory apparatus. B. Stylet with distal tip amplified, from another specimen of Noheji River. C. Stylet from specimens from Jusan Lake. (after Ax 2008). Morphological notes. Body length up to 0.8mm; eyes present. Gut of specimens from Jusan Lake filled with diatoms. Reproductive system. Male copulatory apparatus with seminal and prostatic vesicle joined by a short intervesicular duct. Prostatic vesicle with extravesicular glands; prostate not encased in proximal stylet. Curved stylet of tuba type (Fig. 40); distally, opening of the stylet thickened at the convexe side; d = µm, a = 15 18µm. Remarks. Several specimens displayed an anomalous course of the wall of the tube of the stylet. Comparable anomalies Ax (2008) found in Macrostomum semicirculatum Ax as well. He inpreted that anomaly as a result of a developmental disorder. Macrostomum hamatum Luther, 1947 (Plate X: R; Fig. 20; Tabs 4, 5, 10) Type locality. Off Zoological Station Tvaerminne, Gulf of Finland, BAL; leg. 27. Aug. 1943; types: deposition not recorded. Habitat. Mid-littoral benthal and stygal of sandy beaches (Otoplana zone) down to 40cm sediment depth, mud, salt-marshes, shore pools, stones, Scirpus uniglumis Link, Juncus gerardi Loisel, Aster tripolium L., down to 0.5m water depth, occurrence from June to August, T = C, oligohalinicum. Geogr. distribution. BAL: Gulf of Finland (Tvaerminne, Henriksberg, Mögloet, Kallvassa, Krogarviken, Vikarskär, Bönholmsviken, Långskär, Storlandet), Baltic Sea (Kieler Bucht, Sweden: skerry coast off Stockholm, Korpmaren, Askö Laboratory), Poland (Zalew Wiślany); ANE: North Sea (North Frisian Islands: Sylt, Netherlands: Oosterschelde, Yerseke), North Atlantic (Iceland: Holtsós lake); ANW: Gulf of Maine (Canada: New Brunswig: Pocologan, Campobello Island: Upper Duck Pond) (Armonies 1987, 1988a, Ax 1951a, 1954, 2008, Ax & Armonies 1987, Den Hartog 1974, 1977, Fenchel & Jansson 1966, Karling 1974b, Luther 1960, Schockaert et al. 1989). Morphological notes. Body length up to 2.0mm, typically macrostomid-shaped, anteriorly bluntly truncated or rounded, posteriorly with spatulate tail, bluntly rounded and with adhesive glands; in i.l. whitish; in t.l. colourless, with intestine taking on yellowish colouration when diatoms ingested. Rhabdites intensively abundant in anterior and posterior body-end; in packets of 2 to 4 rods. Packets measure 21µm in length (m.f.s.) at spatulate tail. 94

95 Anterior body end with two rhammite tracks originating from glands located latero-caudal of pharynx simplex. Rhammites also present in region of gut and posterior body. Tactile cilia along anterior margin. Black eyes small, 5 to 6 pigment granules, at posterior border of brain (one specimen found, without eyes). Excretory system indistinctly determined with lateral stems. Intestine with great number of Minotian cells. Reproductive system with bilateral testes and ovaries. False seminal vesicle present. Muscular seminal and prostatic vesicle divided by strong sphincter; intervesicular duct absent. Extra-vesicular prostatic glands present; interior of prostatic vesicle with 3 to 4 chambers (ciliated?). Distal part of prostate encased by proximal part of stylet. Stylet (Plate X: R) (102µm long) narrow, elongate funnel, slightly curved in one plane with short tip at an acute angle. Length of stylets from Canada 108µm, 111µm and 126µm and from the island of Sylt up to 150µm (Ax & Armonies 1987). Female system composed as usual. Common oviduct present, the opening of which into the female atrium provided with tall cells forming the cellular closure apparatus. Distally, female atrium with long cilia. Passage cells between common oviduct and atrium present. Vagina if present, short. Cement glands open around female pore to the exterior. Gonopores separate. Ecological notes. Macostomum hamatum was observed by Armonies (1987) in saltmarshes of the North Frisian Island Sylt at salinities under 12. Individual abundances fluctuated between 2 and 64 ind./10cm², proved a clumpy pattern. After Ax (1954) the species is a characteristic form of brackish water. Autecological characterisation. The species predominates oligohaline areas ( ) consisting of coarse sandy sediments (Armonies 1987, Ax 1954, Den Hartog 1977, Karling 1974b, Luther 1947, 1960). Macrostomum hustedi Jones, 1944 (Plate V: L; Fig. 25; Tab. 1) Synonymy. Archimacrostomum hustedi: Ferguson 1954; p. 141, tab. I. Type locality. Duxbury Bay, Massachusetts, USA, ANW; leg. Aug. Sept ; types: USNM-W. Habitat. Eulittoral tidepools, mud-flats, marine. Morphological notes. Body length up to 860µm; typically macrostomid-like, shape teardrop with blunt anterior end and slender tail; tail spatulate with disk-shaped outline and surrounded with adhesive papillae. Colour white, with brown pigment on dorsal surface of anterior body-third (in i.l.); this pigment becomes very scattered posteriorly and on ventral surface. Clear areas formed dorsö-lateral to eyes. Dorsal surface with sensory hairs, more concentrated at anterior terminal region. Body sparsely distributed with a single kind of compound rhabdite or small rhabdite gland; these rhabdites concentrated on tail of dorsal surface, scarce on ventral surface of body. Adhesive glands present. Chromosome number 2n = 12. Reproductive system with separate gonopores. Proximal stylet encases granular portion of the prostatic vesicle which is weakly supplied with prostatic glands cells. Stylet has orifice about one-third distance from point to base (Jones 1944, p. 349). Stylet (Plate V: L) directed posteriad, length (d = 53µm) calculated from plate 1 fig. 3 (Jones 1944). Female system consisting of vagina surrounded by a mass of cement glands, female atrium, common oviduct and paired oviducts. Common oviduct indistinguishable from female genital atrium. Oviducts leading from ovaries serving as ovo-vitellaria (Jones 1944, p. 349: Since, in this animal, the ovary shows histoligcal resemblance to the ovo-vitellaria or germaria of the cumulate alloeocoeles, it is suggested that this organ has a dual, or compound function as producer and nourisher of ova. ). 95

96 Remarks. Faubel & Warwick (2005) accepted the transfer of Macrostomum hustedi to the genus Archimacrostomum Ferguson However, because of a new interpretation of the figures given by Jones, the prostatic vesicle of Macrostomum hustedi totally encases the prostatic glands in the proximal part of the stylet and doesn t warrant extravesicular glands. The species is re-transferred to the genus Macrostomum. Macrostomum ideficis Schmidt & Sopott-Ehlers, 1976 (Plate VII: E) Type locality. Puerto Nuñez, Galapagos Islands, Ecuador, PSE; leg. P. Schmidt, Febr to March 1973; types: ZMU-G, P Habitat. Eulittoral benthal and stygal, sandy sediments, marine. Morphological notes. Body length up to 0.6mm, typically macrostomid-shaped, extermities broadly rounded, narrowing posteriorly to spatulate tail with adhesive glands at caudal rim; waists at level of pharynx and caudal of hind gut. In i.l. whitish, I t.l. yellowish to yellowish grey. Tactile bristles space irregularly lateral margin but bristles are most abundant around frontal ends, up to 10µm long, and caudal ends, up to 15µm long. Bundles of rhabdites, in groups with 10 to 12 rods, up to 6µm in length, scattered over entire body surface with greater concentration on tail and frontal body-end. Numerous rhammite tracks present in fore-body, additionally, rhammites tracks extend from latero-caudal parts of pharynx to mouth in a semicircular arc. Eyes absent. Mouth, pharynx, and intestine without any specialities. Reproductive system with bilateral testes and ovaries. Vasa deferentia unite immediately before passing over into the seminal vesicle. False seminal vesicle absent. Seminal vesicle and prostatic vesicle joined by very short intervesicular duct. Granular vesicle obviously not walled by muscle sheath. Stylet (Plate VII: E) slightly bow-shaped tube with distal semicircular thickening at the blunt tip, d = 17 21µm in length; proximal opening a = 7-8µm, distal subterminal opening e = 2 3µm. Female system composed as usual. Female atrium walled by a thick, obviously syncytial epithelim. Gonopores separate. Ecological notes. Macrostomum ideficis settled dominantly the moist sand stratum of the upper beach slope above mlwl at low tide. From a total of 1,238 individuals collected, 1,182 individuals (95.5%) were distributed between 130cm and 210cm above chart datum (mlwl) (Schmidt & Sopott-Ehlers 1976). Macrostomum incurvatum Ax, 2008 (Fig. 41, Plate X: U) Type locality. Etang de Salses, Gulf of Lion, MED; leg. Prof. Dr. Ax, Sept. 1962; types: deposition not recorded. Habitat. Supralittoral benthal, medium sand, salinity between 10 and 20, meso- to polyhaline. Morphological notes. Body length up to 1.0mm, colourless; two small black eyes present. Reproductive system. Male copulatory apparatus (Fig. 41A) with seminal and prostatic vesicle joined by a long intervesicular duct. Prostatic vesicle with extravesicular glands; prostate not encased in proximal stylet. Stylet curved, hook shaped, with distal pointed tip bent retrally at about 180 (Fig. 41B, C); distal opening of the stylet subterminal; d = µm. 96

97 Fig. 41. Macrostomum incurvatum. A.Dorsal view of posterior body half in sqash preparation. B. and C. Stylets of different specimens. D. Distal pointed tip of the stylet. After Ax Macrostomum inductum Kolasa, 1971 (Plate V: P) Type locality. Aquarium in Greenhouse of Poznań, Poland, Europe; leg. 10. Febr. 1970; types: deposition not recorded. Habitat. Aquarium, sand, water plants and algae, T = 25 C, freshwater. Morphological notes. Body length up to 1.3mm, macrostomid-shaped, anterior end broadly rounded, and posterior adhesive tail spatulate with slightly pointed end. Distal tubes of adhesive glands at posterior rim of body, up to 14µm in length. Black eyes present. Body margin spaced irregularly with ciliary tufts, up to 40µm long. Rhabdites in groups of seven to nine. Reproductive system with bilateral testes and ovaries. Common vas deferens absent. Intervesicular duct enter in common with extra-vesicular prostatic glands the prostatic vesicle. Spheroidal granular bodies dispersed in the prostatic vesicle; distal part of the latter encased in the proximal funnel of the stylet. Stylet (Plate V: P) funnel-shaped, a = 28µm, distal part hooked at an angle of about 90 and spirally coiled; length of stylet µm (? d). Distal stylet ends with short denticle bent concentrically laterad to the convex side of the stylet. Distal opening subterminal. Female system composed as usual. Common oviduct present. Female atrium ciliated. Gonopores separate. Macrostomum inflatum Beklemishev, 1951 (Plate X: O) Type locality. Krenal of river Kama, Perm, RU-E, Europe; leg. 22. May 1919; types: deposition not recorded. Habitat. Krenal, pools, freshwater. Morphological notes. Species resembling Macrostomum hystricinum Beklemishev, Reproductive system with bilateral testes and ovaries. Bow-shaped stylet comparable to stylets of the Macrostomum ruebushi group (especially M. rossicum Bekl.) (Plate X: O). The stylet differs from the stylets of this group through the proximal, globularly shaped distention in some distance from the proximal base (the proximal half looks like an oil lamp); base of stylet intensively indented. 97

98 Macrostomum infundibuliferum Plotnikov, 1905 (Plate VIII: O) Type locality. Waters of the community Korobeinikovo, Tomsk, Siberia, EPA; types: unknown. Habitat. Phytal of swamps, freshwater. Morphological notes. Body length up to 2.0mm, outline macrostomid-like with rounded anterior end and spatulate tail region. Eyes present. Rhabdites in groups with 2 to 10 rods, ciliary tufts space regularly along margin and spines at extremities. Reproductive system with bilateral testes and ovaries. Common vas deferens distended to false seminal vesicle. Stylet (Plate VIII: O) bow-shaped tube, gradually tapering from a smooth rimmed portion to a blunt point, distally somewhat more bent than proximally, outer convex wall thicker than the concave wall. Distal opening (e) subterminal on the concavity of this curve. Gonopores separate. Macrostomum intermedium Tu, 1934 (Plate X: S) Type locality. Campus of Tsing Hua University, China; types: unknown. Habitat. Pools, freshwater. Morphological notes. Body length generally more than 1.0mm long but usually less than 2.0mm, typically macrostomid-shaped with extended tail region, anterior end rounded, posterior end spatulate with truncated end and adhesive glands upon; colour milky, with intestine taking on colouration with ingested food. Spines single or in tufts more abundant at extremities. Eyes reniform, close to the pharyngeal wall. Rhabdites numerous, prominent, spreading over body surface. Protonephridia not observed. Mouth unusually long, occupying about one-half of pharyngeal cavity. Reproductive system with bilateral testes and ovaries. Stylet (Plate X: S) 225µm long, slightly undulant in one plane, proximally funnel-like, distally broadly bent forming a round hook with pointed tip. Intervesicular duct present. Gonopores separate. Female system composed of usual components and morphology. Ecological notes. M. intermedium lived all year round but sexual maturity was attained only in cold months. Specimens moved slowly on substrates; swimming freely in the water was not observed unless specimens would be strongly stimulated. Specimens withstood radical changes in the environment, such as lowering of ph and oxygen content in aquaria. Macrostomum ismailiensis Beltagi, Ibrahim & Mostafa, 2001 (Plate VI: D) Type locality. Ismailia canal, Moustorod District, Cairo, Egypt, NAF; leg. Beltagi; types: DZASU-C, TRM1. Habitat. Pelagial phytal, within Elodea canadensis L.C. Rich. in Michx. and Eichhornia ceassipes (Mart.), freshwater. Geogr. distribution. NAF: Egypt (tributaries of Nile: Shebin El-Kanater canal, river Nile at El-Gamaa bridge) (Beltagi et al. 2001). Morphological notes. Body length up to 1.8mm, width 0.4 to 0.6mm, oval in shape with broadly pointed anterior end and broadly rounded spatulate posterior end, maximum width at level of first body-fourth, pale white in i.l. Sensory hairs and spines absent. Adhesive papillae at ventral rim of last body-sixth. Brownish black, reniform eyes paired. Brain dispatches four pairs of nerve stems as following: anterior nerve stems (two pairs), antero-lateral nerve stems, lateral nerve stems, and postero-ventral nerve stems forming a circumpharyngeal nerve ring. 98

99 Adenal bundles of rhabdites are more abundant dorsally than ventrally whereas exceedingly large numbers of rhabdites are dispersed in dorsal and lateral tissues of the anterior body-end. Epidermis with intra-epithelial nuclei and crossed by the necks of adenal mucous glands. Body muscle wall structured as usual; dorso-ventral muscle fibres present in parenchymatous parts of body. Protonephria not found. Intestine walled with fine outer longitudinal and inner thick circular muscle layers. Predator on individuals of Cyclopoida and Cladocera. Reproductive system with bilateral testes and ovaries. Distally, vasa deferentia join to a short common vas deferens which enters proximally the seminal vesicle. The seminal vesicle is divided into a proximal vesicle surrounded by a very thin muscular layer ( false seminal vesicle after Beltagi et al. 2001) and a distal vesicle walled with an outer longitudinal and inner circular muscle layer interspersed by few diagonal muscle fibres. Both the vesicles are divided by a sphincter. Seminal and prostatic vesicles joined by a short intervesicular duct. Prostatic vesicle subdivided distally into interciliary chambers, is surrounded with numerous extravesicular glands which pour their prostatic contents into the distal part of the prostatic vesicle. The distal part of the prostate passes over into the proximal part of the stylet. Stylet distad slightly tapering, 180µm in length, provided distally with characteristic tuba-like thickening (Plate VI: D). Female system consisting of bilateral ovaries, oviducts joining mediad into short common oviduct, female genital atrium walled with outer longitudinal and inner circular muscle layer, and distal gonopore. Vagina obviously absent. Cement glands characteristically arranged in the surrounding tissue of the female atrium, passes over into the distal part of the latter. Gonopores separate. Macrostomum japonicum Okugawa, 1930 (Plate X: H) Type locality. Biwa-Ko, Honshu, Japan, EPA; types: unknown. Habitat. Sublittoral phytal and benthal of lakes, ponds and pools, freshwater. Morphological notes. Body length up to 1.5mm by 0.25mm maximum width in mid-body, outline macrostomid-like with broadly rounded anterior and short spatulated tail region. In t.l. colour rather dark yellowish brown, intestine reddish brown to orange; in i.l. body white. Small black eyes dorsal at level of frontal portion of pharynx. Rhabdites in bundles (2 to 6 per bundle after Okugawa 1930) and compact in their distribution. Rhammite tracks not observed. Powerful pharynx simplex, slit-shaped, with intensive pharyngeal glands extending dorsolateral up to the level of the frontal testes. Sensory rigid cilia space along whole margin. Reproductive system with bilateral testes. Stylet (Plate X: H), about 170µm in length, a long slender funnel with somewhat undulant main axis; the distal portion is bent from the main axis to about a right angle; the distal part is bent in a semi-circle. Distal terminal opening oblique and not sharply pointed. Sperm cell with small round head and winding tail; setae absent. Female system composed as usual. Gonopores separate. Remarks. Macrostomum japonicum abounded dominantly in the months August and September (Okugawa 1930). Macrostomum johni Young, 1972 (Plate VII: *H) Type locality. Llyn Cwellyn, Caernarvonshire, North Wales, Europe; leg. Dec. 1968, Febr and 1970; types: BMNH-L, Habitat. Littoral phytal, Agropyron repens (L.), Juncus subnodulosus Schrank, Littorella lacustris L., Phalaris arundinacea L., down to 1.5m, freshwater. Geogr. distribution. EUROPE: England (North Wales, Western Midlands: upland calcium-poor lakes); NEO: (Brazil (Rio Grande do Sul: Santo Antõnio da Patrulha) (Young 1972b, Young 1973, Gamo & Leal-Zanchet 2004). 99

100 Morphological notes. Body length up to 1.3mm, macrostomid-shaped with slight constriction or waist in region of male stylet, extremities rounded, in t.l. colourless, with intestine taking on colour of food content. Sensory bristles, up to 25µm in length though 12 to 20µm are common, sparsely scattered all around the body in tufts of up to six cilia but on average two to four; at extremities of body bristles single and more abundant, especially at posterior body-end. Adhesive papillae present at posterior end. Eyes absent. Epidermis with mucous cells. Body muscle wall structured as usual; inner diagonal fibres present but varying from location to location in the body. Dorso-ventral muscle fibres were observed. Rhabdites scattered all over the body surface in bundles of up to 9 though 4 to 6 are common; rhammite tracks weakly developed. Alimentary canal typical as in other Macrostomum species. Muscel fibres extend posteriorly and laterally from pharynx and radiating fibres from gut to body muscle wall; intestine ciliated, walled with inner circular and outer longitudinal muscle fibres. Reproductive system with bilateral testes and ovaries. Vasa deferentia join in mid-line to a vas deferens at level of posterior gut; according to state of maturity the vas deferens distend to a false seminal vesicle which opens via a short contriction into the seminal vesicle. Intervesicular duct supplied with very few muscle fibres, present. Walls of seminal and prostatic vesicles with spiral muscles. In slightly squashed specimens, stylets 80-98µm long if two planes of stylet were obvious. Stylet length after Gamo & Leal-Zanchet (2004) 40-45µm. Distal termination blunt and cowl- (hood-) shaped with thickened wall; opening subterminal on the concave side; proximal opening a = µm. Female system composed of usual components. Common oviduct present. Cellular closure apparatus present but poorly developed. Gonopores separate. Remarks. Specimens could only be collected from December to Februar. Monthly sampling from November 1968 to October 1969 (August excepted) did not reveal any specimens outside these months (Young 1972a, p. 254). Specimens were sampled from the littoral zone of upland, calcium poor, unproductive lakes in Caernarvonshire (Young 1972b, Young 1973). Macrostomum karlingi Papi, 1953 (Plates IV: J, IX: F) Synonymy. Macrostomum sp. (saggio n. 25) Papi, 1951; p , fig. 21. Macrostomum sp. Müller & Faubel 1993; p. 370.? Macrostomum spec. Ax 1957; p. 429, tab. 1. Type locality. Rivulet Sorettianoja near Nilivaara, Parish of Kittilä, Finland, Europe; types: in author s collection. Habitat. Krenal, fluviatile benthal, sand, on pebbles, stones, detritus, flooded litter of conifer needles and soil, phytal of mosses, freshwater, distributed boreo-alpine. Geogr. distribution. EUROPE: Germany (Schwarzwald: Falkau; Thuringia; eastern Hesse), Italy (Alpi Apuane, alt. 1,180m: Province of Lucca; Fosso Contesora; small stream near Asciano), Poland (Poznań, Sudeten mountains, Krakow), (An Der Lan 1967, Kolasa 1973a, 1974, 1983, Lanfranchi & Papi 1978, Luther 1960, Papi 1953, Schwank 1986). Morphological notes (Plate IV: J). Body length up to 1.2mm; anterior body truncated, with narrowings of body at level of mouth and behind genital organs, rear body-end spatulate, its rim furnished with adhesive glands. Colourless, with intestine yellowish in i.l. and grey in t.l. Longer bristles (tufts of two cilia, according to Kolasa 1973, fig. 5B) space irregularly along margin (up to 21µm); anterior end with bristles of 10 to 11µm in length. Body muscle wall structured as usual. Eyes, pale-brownish in colour, anterior to pharynx. Rhabdites single but mostly in groups in anterior and posterior region of body. Rhammite tracks present. 100

101 Reproductive system with bilateral testes and ovaries. Vasa deferentia join to vas deferens distended to false seminal vesicle. Stylet d = 60-64µm (45-50µm after Kolasa 1973), proximal opening up to a = 18µm (14-24µm after Kolasa 1973); stylet funnel-like, curved distad (Plate IX: F. Distal opening subterminal. Female system composed of usual compartments. Cellular closure apparatus indistinct. Female atrium only distally ciliated. Gonopores separate. Stylet of M. hystricinum group. Ecological notes. Kolasa (1974) is of the opinion that the original area of distribution of M. karlingi should be warmer habitats (derived from studies near of Poznań) than boreo-alpine regions because only one specimen could be detected at the hitherto existing locations. Remarks. Müller and Faubel (1993) found in the Elbe River estuary an immature specimen which looked similar to the morphology of Macrostomum curvituba the exception being the present of paired eye spots. This species could be sampled later again (July 2002) in full sexual maturity. The morphological and antomical organisation was identical with M. karlingi. The stylet length (d) varied between 56µm to 60µm; the proximal opening (a) measured 16.5µm. According to the outline of the stylet given in Rixen (1961, fig. 17), the species Macrostomum spec. Ax, 1957 (see Fig. 11F) found in the Elbe River near Harburg, looks identical with M. sp. Müller & Faubel 1993 and, therefore, with M. karlingi Papi. Remarks. Schwank (1986) designated M. karlingi as a true stygobiont species. Fig. 42. Macrostomum kawamurai Okugawa; A. C. Stylets of divergent form based on specimens differently squashed (prepared by Prof. Dr. O.-A. Timoshkin). D. Micrograph after Okugawa Bars 20µm. Macrostomum kawamurai Okugawa, 1930 (Fig. 42) Type locality. Lake Biwa-ko, Honshû, Japan, EPA; types: deposition not recorded. Habitat. sublittoral phytal, algae and weeds, fresh-water. Morphological notes. Body length up to 2.5mm by 0.5mm width, oval in shape with bluntly pointed anterior end and posterior spatulate plate with adhesive caudal rim. The basic colour is pale, with light yellow intestine taking on colour of food content. Eyes present at the antero-dorsal level of the pharynx; they are kidney-shaped with distinct lenses. Rhabdites abundant, in groups of three or four; rods straight or curved, pointed at one end and blunt at the other. Reproductive system. Testes and ovaries bilateral; ovaries seem to be lobed. Seminal and prostatic vesicle joined by a small intervesicular duct. The stylet is about 150µm in length (d). After Okugawa (1930), the terminal portion is somewhat irregularly twisted and the tip is bent nearly perpendicular to the axis of the main portion (Fig 42). The distal opening is terminal, somewhat truncated obliquely. Remarks. Ferguson (1940b) synonymised Macrostomum kawamurai with Macrostomum saifunicum Nasonov, based on the outline of the distal portion of the stylet figured by Okugawa in 1930, Fig. 8. In 1953, Okugawa accepted the synonymy of M. kawamurai with M. saifunicum emended by Ferguson (1940b). However, the difference between both the stylets is distinctly to see in the absence and presence of the fine lamella at the distal bend of the stylet. Obviously, Ferguson was stimulated to synonymise both the species because of the drawing made by Okugawa based on the distal end figured by Okugawa, which could be 101

102 interpreted to be provided with a fine lamella as in M. saifunicum. However, the distal drawing should only express the irregular twisting of that part of the stylet in more than one plane. The absence of a fine lamella could be documented in species collected by Timoshkin in 1997 in Lake Biwa (Timoshkin pers. com.). Macrostomum kepneri Ferguson & Jones, 1940 (Plate XI: A) Synonym: Macrostomum ruebushi var. kepneri Ferguson & Jones, 1940; p , figs 1-4. Type locality. Tanner s Creek at Colley Avenue Bridge, Norfolk, Virginia, USA, ANW; types: USNM-W, Habitat. brackish water. Geogr. distribution. ASW: Caribbean Sea (Jamaica: Discovery Bay) (Therriault & Kolasa 1999). Morphological notes. Body length up to 1.12mm by 0.16mm width, anterior end rounded, posterior end semi-pointed, colourless, with intestine taking on colour of food content. Many unusual large amoebocytes (10.5µm) in lateral parenchyma. Epidermis with oval mucous glands. Anterior end supplied with tufts of cilia up to 9µm long; posterior end with spines up to 22µm in length. Rhabdites in groups of 7 to 9, few in number, located laterally on both ventral and dorsal surface. Rhammite tracks in fore-body, the glands of which originate above and below brain. Pharyngeal walls entered by two types of glands, rhammites and a system of streamers supplying a product of granular nature. Paired eyes immediately behind and dorsal to the brain, being partially embedded in it. Excretory system with lateral stems extending along length of body; very large flame cells present. Excretory pore not observed. Reproductive system with bilateral testes and ovaries. Vasa deferentia unit to very short common vas deferens; false seminal vesicle absent. Seminal vesicle ciliated. Prostatic vesicle without ciliated chambers. Stylet (Plate XI: A), 67.5µm in length, a simple extended funnel with terminal bend; distally pointed. The distal opening subterminal, e = 15µm, should be seen as lateral aperture. Proximal opening a = 15µm. Female system composed of usual compartments. Cellular closure apparatus indistinct. Female atrium ciliated. Gonopores separate. Sperm-cell, 75µm long, with two setae. Macrostomum korsakovi Nasonov, 1926 (Plate XI: R) Synonym: Macrostomum obtusum korsakovi Nasonov, 1926 Macrostomum nassonovi Ferguson 1939; p , fig. 6. Type locality. In waters of the Peterhof, St. Petersburg, RU-W, Europe; leg. Rimsky- Korsakov Aug. 3, 1921, Nasonov Sept. 8, 1921; types: unknown. Habitat. Freshwater. Morphological notes. The description of Nasonov (1926) characterised by its paucity of information, presents only details on the male genital complex. Reproductive system with bilateral testes and ovaries. False seminal vesicles present. Prostatic vesicle provided with a distal rosette of extra-vesicular prostatic glands spreading fan-wise from the distal part of the prostate. Stylet (Plate XI: R) a lengthened tube with proximal slender funnel extending from a smooth rimmed base to a blunt truncation terminally; the main axis of the stylet has two right angle bends in its course. Gonopores separate. 102

103 Macrostomum leptos An Der Lan, 1939 (Plate VII: F) Type locality. Lake Ohrid, Makedonia, Europe; leg. July to Aug. 1937; types: deposition unknown. Habitat. Sublittoral benthal, mud, down to 33m water depth, freshwater. Morphological notes. Body length up to 0.8mm, terminal rounded but posterior end more blunted, spatulate with slight waist. Reproductive system. Only stylet kown. Stylet (Plate VII: F) a bow-shaped, simple, extended funnel of tuba-type, flexed at an obtuse angle of about 110, and a distal spiral bend in two planes. Distal end blunt, slightly thickend. Distal opening subterminal. Macrostomum lewisi Ferguson, 1939 (Plate VII: *M; Tab. 1) Type locality. White Oak Canyon Falls, Greene County, Virginia, USA, NEA; types: USNM-W, 20448, Habitat. Rhitral, phytal, in masses of algae and mosses, freshwater. Morphological notes. Body length up to 1.3mm, typically macrostomid-like, anteriorly blunted, posterior end spatulate with adhesive glands, colourless. Reniform eyes and rhabdites present. Rhabdites on spatulate disk measure 16µm in length, grouped to 4 or 5. Spines at the extremities, tufts of cilia (34µm long) more prominent along margins. Protonephridia with bilateral stems; external opening not observed. Chromosome number n = 3. Reproductive system with bilateral testes and ovaries. False seminal vesicles present. Stylet (Fig. x) tubular containing two right angle bends in its main axis; length of stylet 104µm. Basal rim dentate while the distal part is provided with a unique knobbed process. The enlarged distal end is quite asymmetrical; the opening terminal. The main distal, subterminal, genital canal is provided with a dentate, circumferential ornamentation. Gonopores separate. Macrostomum lignano Ladurner, Schärer, Salvenmoser & Rieger, 2005 (Plate VII: I; Tab. 1, 3) Synonymy. Macrostomum sp. Ladurner, Rieger & Baguña, 2000; p , figs 1-9. Type locality. Laguna di Marano, Lignano, N E, Italy, Northern Adriatic Sea, MED; types: NHM-W, 4578, Habitat. Mid-littoral benthal of highly sheltered beach, upper few millimeters of thinly oxidised surface of sediments, marine. Morphological notes. Body length up to 2.0mm, macrostomid outline with very slight constrictions at level of mouth and of genital organs, subdividing the body into head, midbody, and adhesive plate; extremities of body rounded provided with sensory hairs. In t.l. specimens colourless; in i.l. specimens taking on brownish/greenish colouration when diatoms ingested. Small adhesive duo-gland organs arranged ventrally on the ventral rim of the adhesive plate (120 adhesive organs; n = 15). Black eyes at postero-dorsal border of brain. Rhabdites (? single and in bundles of 2 and 3) dispersed over ventro- and dorso-lateral regions of body. Rhammite glands located laterally of frontal gut, extend anteriad; rhammite tracks penetrating brain, open at the frontal border of the head. Pharynx simplex provided with pharyngeal glands which reach far behind pharynx. Reproductive system with bilateral testes and ovaries. False seminal vesicle present. Prostatic vesicle with extra-vesicular prostatic glands. Stylet (Plate VII: I) of Macrostomum 103

104 tuba-group, represents a slender, slightly flexed, funnel-shaped tube with blunt distal opening; terminal opening with slightly asymmetric thickenning. Mean stylet 69µm in length (d), mean a = 14µm. Female system with distal ciliated vagina, which opens into non-ciliated female atrium, and oviduct reduced to cellular valve. Gonopores separate. Cytology. According to Ladurner et al. 2000, adult species of M. lignano consists of a total number of 24,708 ± 3,831 cells from which about 20% are neoblasts. Roughly estimated, 10% of the neoblasts are in S-phase and 0.5% in mitosis. Hatchlings ( µm in length) averaged 5,465 ± 761 total cells. S-phase neoblasts are arranged laterally in two main bands, the areas of male and female gonads. They were never found in the head-region. Obviously, neoblasts give rise to all types of cells including germ cells. Macrostomum lineare Uljanin, 1870 (Plate IX: X) Type locality. Bay of Panajot, Black Sea, MED; types: unknown. Habitat. Brackish, marine. Geogr. distribution. BAL: Poland (Gdansk: Vistula estuary) (Meixner 1938) Morphological notes. Body terminally rounded, macrostomid-like, tail-plate with adhesive glands. Spines, tufts, rhabdites, and eyes absent. Tracks of rhammite glands extend to tip of the anterior end, apparently intertwining at intervals. Reproductive system with bilateral testes and ovaries. Stylet (Plate IX: X) a completely bent spiralled (almost 360 ) and sharply pointed tube. Gonopores separate. Remarks. The stylet of Macrostomum lineare looks nearly identical with the stylet of Microstomum inerme Zacharias, 1894 (Dorner 1902, plate II: fig. 2). Macrostomum longistyliferum Ax, 1956 (Plates IV: N, IX: I) Type locality. Canal du Canet, Etang du Canet, Gulf of Lion, MED; leg. 20 April to 29. May 1952; types: deposition not recorded. Habitat. Benthal of sandy sediments, phytal (Cyanophyceae), saliniy between 6.3 to 8.3, beta-mesohaline. Morphological notes (Plate IV: N). Body length up to 1.6mm, extremities bluntly rounded, posterior end slightly spatulated. Rhammite tracks present, the glands of which at level of pharynx simplex. Eyes present. Rhabdites densely distributed over body-surface. Reproductive system with bilateral testes and ovaries, false seminal vesicle, and intervesicular duct. Stylet (Plate IX: I) a long slender tube, d = 140 to 150µm; distal half of stylet slightly bent; distal tip slightly distended, is terminally bluntly truncated with a lateral incision on the concave side. Female copulatory system not described. Gonopores separate. Remarks. The distribution of the species in the Gulf of Gdańsk was evidently determined not correctly by Demel 1933 (Ax 1959). Macrostomum longituba Papi, 1953 (Plate VII: G) Type locality. Small ditch, north of river Arno, S. Rossore, Italy, Europe; types: deposition not recorded. Habitat. Eulittoral benthal, mud, salinity 2.5, oligohaline. Morphological notes. Body length up to 1.0mm, typically macrostomid-shaped, anterior end broadly blunt, posterior end rounded, last body-third narrowing to spatulate adhesive plate. Tactile bristles around anterior and posterior body-end; anterior bristles 8µm long. Rhabdites single or in bundles distributed over body-surface but more abundant in posterior 104

105 body; length of rhabdites at posterior body-end 12-14µm. Rhammite tracks present. Darkbrown eyes at posterior border of brain. Intestine with Minotian cells. Reproductive system with bilateral testes and ovaries. False seminal vesicle present. Seminal and prostatic vesicle joint by a short intervesicular duct. Stylet (Plate VII: G) a slightly curved, extended, 143µm (d) long funnel with blunt distal tip. Distal tip spoon-like distended, with subterminal opening on the concave side. Proximal opening a = 22.5µm. Female system composed as usual. Female atrium ciliated and with rostral cellular closure apparatus. Gonopores separate. Macrostomum lutheri Beklemishev, 1927 (Plate VII: C, D) Synonymy. Macrostomum tuba: sensu Luther 1905; p. 35, pl. IV: figs nec Macrostomum lutheri: Gieysztor 1930; p. 311, fig. 4.? Macrostomum lacustre Beklemishev, 1951; p. 38, figs Type locality. Lohja, Finland, Europe; leg. Luther, 29. July 1901; types: not deposited, only observations of live specimens in quashed preparation. Habitat. Littoral of shaddowed pond, small rivulet, phytal, Nymphaea sp., freshwater. Geogr. distribution. EUROPE: Finland (Kittilä : lakes Hautajärvi, Lojo), Italy, Poland, Russia (RU-N: Terijoki: Osero Schujtschje), (? Beklemishev 1951, Gieysztor 1939, Luther 1947, 1960, Papi 1951b). Morphological notes. Body length up to 2.0mm, terminally rounded whereas caudal end of body more or less spatulate, colourless transparent, with intestine taking on yellowish colouration of food content. Sensitive bristles all-around lateral body, arranged densier at terminal ends. Eyes of yellow-brown pigment granules, behind crescent brain. Rhabdite bundles (rods up to 13µm long) and rhammite tracks present. Reproductive system with bilateral testes and ovaries. Vasa deferentia unite to vas deferens distending to false seminal vesicle. Intervesicular duct with sparse circular muscle fibres. Prostatic vesicle proximally ciliated, with extravesicular glands (Plate VII: C). Stylet a 210µm (d) long tube with proximal funnel, a = 50µm, distad tapering, slightly spiral, distally with thickened tip and latero-subterminal pore (Plate VII: D). Female genital organ directed backwards, consists of ciliated globular female atrium and distal vagina; distal vagina widens caudad to a diverticulum being less ciliated. Cement glands pour into vagina at transition of vagina into female atrium. Oviduct cellular distally forming a cellular closure apparatus to female atrium. Gonopores separate. Remarks. The doubtful species Macrostomum tuba sensu Luther, 1905 was emended by Beklemishev (1927a) to Macrostomum lutheri based on the figures given by Luther Doubtful is as well, if Macrostomum lacustre Beklemishev is a synonym of M. lutheri as stated by Luther Great differences exist in the dimensions of the stylets and anatomy of the prostatic vesicles. Beklemishev (1951) presented a very detailed drawing from the prostatic vesicle of M. lacustre showing ampulla-like glandular ducts encased by the proximal funnel-shaped enlargement of the stylet and extravesicular glands. If ampulla-like enlargements were developed in the prostatic vesicle of M. lutheri remained unmentioned by Papi (1951a) and Luther (1960). However, the prostatic vesicles both the species are covered by a muscular wall and do not look reduced. For comparison, I reproduced the prostatic vesicle and stylet of M. lacustre given by Beklemishev (1951), on Plate VII: C. Macrostomum magnacurvituba Ax, 1994 (Plate VII: B) Type locality. Mouth of limnic lagoon, off Arctic Station Godhavn, Disko Island, Greenland, ANW; leg. Aug. 1991; types: only live observations. 105

106 Habitat. Eulittoral, benthos, sandy sediments, brackish and freshwater. Geogr. distribution. EUROPE: Iceland (Reykjanes peninsula: Hlidarvatn, lagoon) (Ax 1994, 2008). Morphological notes. Body length up to 1.0mm, waist at level of male organs, spatulate plate, colourless. Eyes absent. Reproductive system with bilateral ovaries and testes. Length of stylets µm, slightly bow-shaped; diameter of proximal opening a = 22-30µm and of distal oblique opening e = 6-8µm; lengths of stylets from Iceland: d = µm (Ax 1974). Proximal part of stylet with longitudinal stripes; distal end of stylet slightly thickened (Plate VII: B). Remarks. After Ax (1994), Macrostomum magnacurvituba and M. curvituba Luther, 1947, are very similar species. Differences are length of stylet, lack of eyes and geographical vicariance in corresponding biotops at border of sea and freshwater. Both species might be adelphotaxa. Macrostomum majesticis Schmidt & Sopott-Ehlers, 1976 (Plate IX: Q) Type locality. Bahía Academy, Santa Cruz, Galapagos Islands, PSE; leg. Schmidt, Febr to March 1973; types: ZMU-G, P Habitat. Eulittoral, benthos, sandy sediments, marine. Geogr. distribution. PSE: Galapagos Islands (Island Fernandina: Cabo Douglas, Punta Espinosa; Island Isabela: Caleta Tagus, Cabo Rosa; Island Pinta: southern beach; Island Santa Cruz: near of Bahía Borrero, Island Baltra: northern beach) (Schmidt & Sopott-Ehlers 1976). Morphological notes. Body length up to 0.5mm, macrostomid-shaped, anteriorly bluntly rounded, posteriorly bluntly pointed indistinct spatulate adhesive plate, in i.l. colour whitish, in t.l. colour grey. Tactile bristles few, up to 12µm long. Epidermis with adenal rhabdites. Rhabdites single or in bundles, particularly more abundant on the spatulate plate. Anterior end with rhammite tracks; in addition, six to seven rhammite tracks extend to both sides of pharynx. Reproductive system with bilateral testes and ovaries. False seminal vesicle and intervesicular duct present. Voluminous duct of prostatic vesicle ciliated. Extravesicular glands enter proximal part of the prostatic vesicle. Further prostatic glands lie in the distal part of the prostatic vesicle which is encased in the proximal part of the stylet. Stylet (Plate IX: Q) a 37 45µm (d) long, slightly S-shaped tube proximally distended funnel-like, a = 9 12µm. Distal tube 2 to 2.5µm in diameter, obliquely truncated with terminal opening. Female system composed of usual components and morphology. Female atrium distally ciliated. Cellular closure apparatus and oviducts not mentioned. Vagina, ciliated, extremely short and surrounded by cement glands. Gonopores separate. Ecological notes. Macrostomum majesticis settles dominantly the lower sandy beach slopes. The abundance is less than 10 animals per 100cm³ sediment. From a total of 244 individuals collected, 213 individuals (87.5%) were distributed between 0cm and 70cm above chart datum (mlwl) (Schmidt & Sopott-Ehlers 1976). Macrostomum mediterraneum Ax, 1956 (Plate VII: P) Type locality. Etang de Sigean, Gulf of Lion, MED; types: deposition not recorded. Habitat. Eulittoral, benthos, sediments of soft, flocculent detritus, marine. Geogr. distribution. MED: Gulf of Lion (Golfe d Aigues-Mortes: Étang de Sigean,), Sea of Marmara (Tuzla) (Ax 1959, Fize 1963). 106

107 Morphological notes. Body length up to 1.5mm, typically macrostomid-shaped, with eyes. Rhabdite bundles distributed over body-surface. Rhammite tracks weakly developed, present in anterior body. Digestive system developed as usual. Minotian cells interspace irregularly ciliated intestinal lining. Reproductive system with bilateral testes and ovaries. False seminal vesicle non-muscular, passes over ciliated seminal vesicle. Extra-vesicular prostatic glands extend into prostatic vesicle at junction between seminal and prostatic vesicle; intervesicular duct indistinct. Stylet 88-90µm long (103µm Ax 1959), slightly bow-shaped, extended funnel with distal blunt, solid, clubbed point (Plate VII: P). Distal opening subterminal. Female system composed of usual components and morphology. Female atrium with cellular closure apparatus, nonciliated. Ecological notes. According to substrate and salinity of the two localities known up to date, Macrostomum mediterraneum settles saline lagoons and ponds rich in salinity of extreme lentic coastal areas of arid climates (Ax 1959). Macrostomum minutum Luther, 1947 (Plate VII: L; Tab. 5) Synonymy. Macrostomum tuba? Luther in Purasjoki 1945; p. 11. Macrostomum tuba minuta Luther, 1947; p , figs Type locality. Järnön, Ekenäs, area of Tvaerminne, Finland, Gulf of Finland, BAL, leg. K. Purasjoki, 7. Jan. 1944; types: deposition not recorded. Habitat. Sublittoral benthal, sand, gyttja, clay, down to 24m water depth, salt-marshes, salinity 3.68, oligohaline, freshwater. Geogr. distribution. BAL: Germany (Kieler Bucht: Schilksee, Surendorf, Schlei, Windebyer Noor), Poland (Wolin Island), Sweden (Sundholmen); ANE: North Sea (North Frisian Islands: Sylt, Amrum, Elbe river) (Armonies 1987, Ax 1951a, 1957, 2008, Hellwig 1987, Kolasa 1973, Luther 1960, Schmidt 1972b). Morphological notes. Body length up to 0.5mm (1.5mm after Kolasa 1973), maximum width at level of pharynx behind mid-body, anterior end truncate, posterior end narrowed to adhesive spatulate plate, bluntly rounded. Colour of body whitish (yellowish and opaque after Kolasa 1973). Eyes absent; rhabdites adenal. Tactile bristles border anterior and posterior end of body, 3.2µm in length. Reproductive system with bilateral testes and ovaries. False seminal vesicle present, intervesicular duct absent. Stylet slightly bow-shaped tube, with thickened wall around distal pore, d = 75-82µm long (Plate VII: L). Measurements of the length after Hellwig (1981) d = 72µm and Armonies in Ax (2008) d = 100µm and 105µm. Female copulatory system not observed. Ecological notes. Specimens of M. minutum were observed by Hellwig (1987) in the supralittoral belt of sandy slopes and in salt-marshes (Armonies 1987) of lentic areas of the North Frisian Island Sylt. Sexually mature specimens were collected in late summer and late winter. The abundance of 1 to 4 specimens per 2cm² is very low Hellwig 1987). Macrostomum montanum Kaiser, 1974 (Plate V: J) Type locality. Erfgrundbach, Thuringia, Germany, Europe; types: deposition not recorded. Habitat. Krenal, phytal, Sphagnum sp., freshwater. Morphological notes. Body length up to 2.5mm, typically macrostomid-shaped, anteriorly truncated, posteriorly rounded spatulate tail disk-like, adhesive papillae present. Black eyes. 107

108 Reproductive system with bilateral testes and ovaries. Stylet (Plate V: J) 75µm in length, S-shaped funnel, slightly spiral. Proximal opening a = 25-30µm. The prooximal part of the stylet with folds or crenated as Beklemishev (1951) described for M. phytophilum. Stylet ends distally with a more or less rounded process; opening at the distal concavity laterosubterminal. Autecological characterisation. Titanophobic, cold stenotherm, montane form (Kaiser 1974). Macrostomum mosquensis Beklemishev, 1951 (Plate IX: K) Type locality. Moskwa river, Russia, Europe; leg. Sept. 9, 1936; types: deposition not recorded. Habitat. fluviatile, freshwater. Morphological notes. Body colourless, with strong black eyes arranged closer to each other than normally. Posterior body tail-like with blunt rear end; posterior rim provided with adhesive glands. Rhammites extend to anterior margin of body in broad tracks. Reproductive system with bow-shaped stylet; stylet proximally funnel-shaped, tapers gradually distad. Distally, the stylet terminally distended, opens up with an oblique terminal opening (Plate IX: K). In the hind body, sperm collects in a false seminal vesicle ( vesicula seminalis spuria after Beklemishev) representing the distended common vas deferens which passes over into the seminal vesicle. Seminal and prostatic vesicle connected immediately; an intervesicular duct is absent. The distal part of the prostatic vesicle is encased by the proximal funnel of the stylet. Extravesicular prostatic glands enter proximally the prostatic vesicle close to the junction of seminal and prostatic vesicle. Female genital organs not described. Macrostomum mystrophorum Meixner, 1926 (Plate XI: Q) Type locality. Styria, Austria, EUROPE; types: deposition not recorded. Habitat. Crenal, phytal of mosses, rheophilous, freshwater (after Meixner 1926); temporary pools, benthal on muddy sediment, phytal between algae, T = C, ph = 8.5 9, S = 5.15, oligohaline (after Papi 1953). Geogr. distribution. MED: Ligurian Sea (S. Rossore near Pisa: north of river Arno) (Meixner 1926, Papi 1953). Morphological notes. Body length up to 1.5mm, anteriorly rounded or bluntly pointed, greatest width in mid-body, posterior end narrowing to adhesive, rounded, spatulate plate, colourless, with intestine taking on colouration of food ingested. Tactile bristles along anterior margin, 10 to 13µm long, some space irregularly along lateral margin. Rhabdites distributed over body-surface, most abundant in anterior and posterior body-ends, ventrally more scarcely distributed than dorsally. Eyes present. Intestine with Minotian cells. Reproductive system with bilateral testes and ovaaries. False seminal vesicle and intervesicular duct walled with circular and longitudinal muscle fibres present. Extravesicular glands enter prostatic vesicle near entrance of intervesicular duct. Strong retractors extend from prostatic vesicle to ventral body muscle wall. Stylet (Plate XI: Q) a slender, extended funnel, d = 134µm (Papi 1953) (Meixner 1926: d = up to 100µm), with distal end hooked in a rounded bend; proximal opening a = 29.5µm, distal opening terminal, e = 5µm. Female system located more rostrally than usually. Ovaries at end of anterior body-half. Female pore just behind mid-body. Oviducts join to common oviduct which enter the female atrium via cellular closure apparatus. Female atrium ciliated. Vagina short. Cement glands enter female pore. Gonopores separate. 108

109 Remarks. In 1926, (p. 602, 619, fig. 7) Meixner presented only a very short description of M. mystrophorum with an account on the stylet and some details to the posterior spatulate plate. After Meixner (1926), M. mystrophorum is a Leitform der reophilen Quellmoosfauna Mittel- und Obersteiermarks, Austria. The complete description with more details to the type locality announced for later times, were never published. In 1953, Papi presented a complete description of Macrostomum mystrophorum Meixner from the Mediterranean coast after that this report is given. If the populations of the Steiermark and Ligurian Sea (estuary of river Arno) are identical remains questionable (cf. Ax 2008, p. 114). Macrostomum nairobiensis Young, 1976 (Plate XI: M) Type locality. Wellcome Dam, Kabete, Nairobi Area, Kenya, ETR; leg. 24. March 1972; types: BMNH-L, Habitat. Sublittoral phytal, freshwater. Morphological notes. Body length up to 1.0µm, typically macrostomid-shaped, extremities rounded, distinct waist at level of femal atrium, colourless (t.l.), whitish (i.l.). Posterior end evidently without adhesive glands. Semi-rigid bristles single or in tufts of up to 5 along lateral margin; anterior end with bristles, up to 10µm long. Rhabdites scattered in groups of 2 to 12, though mostly 5 to 8, over entire body surface. Rhammite tracks present but weakly developed. Eyes in dorso-posterior position of brain. Reproductive system with bilateral testes and ovaries. False seminal vesicle absent. Seminal and prostatic vesicle connected by intervesicular duct. Stylet (Plate XI: M) hookshaped, slightly bent in another plane as indicated by the arrow. Distal opening terminal. Measurements: from proximal base to distal bent 93µm, from distal tip to proximal border (not d) 80µm, length of hook 53µm. Female system as usual. Female atrium with cellular closure apparatus rostrally but did not appear to be well developed. Cement glands present. Macrostomum niloticum Beltagi, 1972 (Plate VII: *N) Type locality. Shebin El Kanater, Egypt, Africa; leg. July to Aug. 1969; types: deposition not recorded. Habitat. Sublittoral, phytal with Eichhornia spp., Elodea spp., Ceratophyllum spp., Potamogeton spp., freshwater. Morphological notes. Body length up to 2.0mm, anterior end blunt, posterior spatulate, truncated. Adhesive papillae distributed at the ventral surface of the caudal region. Colour pale yellow, with intestine contrasting pale brown due to ingested food. Two brown, reniform eyes at posterior border of brain. Rhabdites distributed at the dorsal surface of the anterior and posterior body-end. Epidermis with intra-epithelial nuclei and rhabdites which are single or in groups of 2 to 6. Body muscle wall structured as usual; dorso-ventral muscle fibres present. Rhammite tracks extend from anterior margin to mouth region. Pharynx simplex entered by pharyngeal cells and provided with protractor and dilatator muscle fibres extending to the body muscle wall. Intestinal cells interspaced with Minotian cells; intestine walled by inner circular and outer longitudinal muscle fibres. Copepods and Cypris sp. were often found ingested. Excretory system not observed. Reproductive system with bilateral testes and ovaries. Vasa deferentia join at entrance into false seminal vesicle. Short intervesicular duct surrounded by strong sphincter which control the supply of sperm into the prostatic vesicle. Proximal half of prostatic vesicle ciliated and distal half filled with granules. Stylet is a bow-shaped tube, 130µm in length, with stronger distal bend and terminal opening. The distal end is slightly thickened whereas the convexe 109

110 part is more thickened than the concave one. Proximal opening a = 9.9µm and the distal opening e = 4.4µm. Female system composed of usual components and morphology. Common oviduct present, passing into ciliated female atrium via cellular closure apparatus. Gonopores separate. Macrostomum obtusum Vejdovsky, 1885 sensu Papi 1951 (Plate IX: G; Fig. 10) Synonymy. Macrostomum obtusum (pro parte) Vejdovsky, 1885; p Type locality. Chotebo, Czechia, Europe; types: unknown. Habitat. Sublittoral, krenal, benthal, on mud, freshwater. Geogr. distribution. EUROPE: Czechia (Chotebor, Tabor), Finland (Lk. Kittilä, Ta. Urjala Raikko), Germany (Franconia), Iceland (Bay of Leiruvogur near Reyklavik) ; Russia (RU-W: St. Petersburg), Ukraine (L viv); BAL: (Poland: Gulf of Gdańsk) (Ax 2008, Bauchhenss 1971, Luther 1960, Papi 1951b). Morphological notes. Body length up to 2.0mm, typically macrostomid-shaped with truncate anterior and spatulate posterior end bordered with adhesive glands. Eyes, adenal rhabdite bundles (rods 12-15µm long) and rhammite tracks present. Bristles at terminal ends and tufts of cilia longer than the entire body-ciliation, space irregularly along lateral margins. Protonephridial system with coiled lateral stems which join caudally and empty to the exterior via an excretory ampulla. Reproductive system with bilateral testes and ovaries. False seminal vesicle present. Seminal vesicle interriorly ciliated, with rosette-like arrangement of gland cells directed antero-posteriorly. Seminal and prostatic vesicle join without intervesicular duct (after Papi 1951b). True long intervesicular duct present (Ferguson 1939c). A small prostatic vesicle lined by spindle-shaped masses of granular material which emanate from accessory glands appended to the proximal region of the prostatic vesicle (Ferguson 1939c). Stylet curved, 80µm long (d), with funnel-like, 18µm (a) wide proximal opening (Plate IX: G). Distal opening subterminal beyond the pointed stylet tunic. Stylet of specimen sampled by Karling (Papi 1951b), 91.2µm long (d). Stylets of specimens after Bauchhenss (1971): d = µm, a = 21-27µm, e = 12-21µm, and Ax (2008): a = 88µm, a = 27µm. Distal opening on the concave side (Ax 2008 and Luther 1960, Fig. 18K) compared to Luther (l. c.) and Papi (1951) on the convexe side. Female system composed as usual. Female pore surrounded with cement glands. Gonopores separate. Ecological notes. Bauchhenss (1971) reported M. obtusum settled pooles or puddles in pastures and ditches, free of vegetation at temperatures from 3 to 13 C. Occurrence was stated from March to June and October. Animals carrying eggs, were observed in April and October. Food diatoms. Luther (1960) rgarded the distribution in the Gulf of Gdańsk as doubtful because the species was found only in freshwaters. Kaiser (1974) reported occurrence in ferruginous waters of helocrenes in meadows of the Lowerharz (Thuringia). Macrostomum ontarioensis Ferguson, 1943 (Plate XI: I) Type locality. Great View Beach, Lake Ontario, New York, NEA; leg. Sept. 1941; types: USNM-W. Habitat. Littoral phytal, algae, altitude about 247 feet, freshwater. Geology: glacial. Morphological notes. Body length up to 0.56mm by 0.14µm width, typically macrostomidshaped, extremities rounded, greatest width anterior to mid-body, from here narrowing to spatulate posterior body-end, colourless, with intestine taking on brownish due to ingested food. Single tactile bristles only along anterior margin, up to 8µm long; ciliary tufts overall, 110

111 posteriorly in groups of 2 to 3, up to 23µm in length, laterally sparse. Rhabdites in groups of 7 to 8 uniformly dispersed of dorsal body-surface. Rhammite tracks in anterior body dorsal and ventral of brain running anteriad. Black eyes paired, just posterior to brain. Mouth and pharynx simplex abundantly supplied with rhammites the glands of which latero-caudal of pharynx; in addition, pharynx supplied with rhabdite tracks. Excretory system of bilateral coiled lateral stems apparently separate; external openings not observed. Reproductive system with bilateral testes and ovaries. False seminal vesicle absent. Intervesicular duct indistinct. Prostatic vesicle proximally with ciliated lumen and distally with numerous rosettes of small granuliferous cells extending far into the proximal part of the stylet. Stylet (Plate XI: I) a sharply terminated funnel-shaped conical tube with two right angle bends in different planes somewhat simulating a coiling; proximal opening crenated, a = 13µm, and distal opening subterminal; length of stylet 32µm. Female system composed of usual components and morphology. Gonopores separate. Macrostomum orthostylum Braun, 1885 (Plates IV: E, IX: A, Figs 92, 93; Tab. 1, 10) Type locality. Lake Peipus (in Russian Chudskoye Ozero), Estonia, Europe; types: not prepared by Braun; voucher specimen: USNM-W, (deposited by Ferguson & Jones). Habitat. Littoral benthal of pools, ponds, lakes or rivers, on mud, gyttja or sand, down to 78m water depth, stagnant and fluviatile waterbodies, freshwater, brackish water. Geogr. distribution. EUROPE: Austria (Danube: Vienna, and tributary streams; Lunz: Mittersee; Wörthersee: 20m water depth; Lower Tauern: Schwarzer See altitude 1,153m), Estonia (Peipussee), Finland (Kittilä, Sorettianjärvi), Germany (Franconia), Italy (Lago Maggiore and Lago di Como 17-30m water depth, Lago Moro, Pavia: garden s pool), Poland (Grodka, Drosdowice, Lake Zbęchy), Russia (RU-E: Perm: river Kama), Switzerland (Lake Maggiore, 78m water depth), Ukraine (L viv); NEA: USA (Virginia: Williamsburg, Norfolk area); ORR: India (Kakinada: brackish water fish-farm); ETR: Kenya (Mombasa: river Mwena, Mariakani: river Maji Ya Chumvi) (An Der Lan 1962, Bauchhenss 1971, Braun 1894, Ferguson & Jones 1940, Hofsten 1911, Kolasa 1979, Luther 1960, Papi 1951b, Shirgur 1980, Steinböck 1926, 1949, Vialli 1926, 1927, Young 1976b). Morphological notes (description is based essentially on Meixner 1915). Body length up to 2.4mm, general shape of Macrostomum hystricinum Beklemishev, terminal body-ends reducing, broadly or bluntly rounded, colour white to yellowish with darker contrasting gut (brown after von Hofsten 1911). Spatulate posterior end slightly waisted behind gut, with adhesive papillae. Eyes and adenal rhabdites present. Rhabdites in bundles dispersed more concentrated over dorsal surface than over ventral surface; posterior caudal rim occupied with prominent adhesive glands. Glands of rhammites develop in region of brain extending in tracks to anterior end. Spindle-shaped rhammites debouch into the rim of mouth and rhabdite glands enter mouth and pharynx simplex. Adenal muscous glands open to the exterior over whole body surface. Digestive lining with lot of Minotian cells edged by a faint basal membrane; intestinum walled with longitudinal and circular muscle fibres. Protonephridia not observed. Reproductive system with bilateral testes and ovaries. False seminal vesicle present (not observed by Ferguson & Jones 1940). Intervesicular duct and extra-vesicular prostatic glands enter prostatic vesicle in common. Distally, crown-shaped region of cells present, which may contribute to form the stylet (Luther 1905, p. 32). Stylet (Plate IX: A) a straight funnel in its main axis terminating in a reduced and greatly sharpened point; measurements of length vary between 61µm (Luther 1960), 142µm (Hofsten 1911) and 63-95µm, a = 10-24µm, e = 11-16µm Bauchhenss (1971); distal oblique opening terminal. Female system composed of usual 111

112 components and morphology. Bilateral oviducts join at entrance to female atrium. Gonopores separate. Haploid chromosome number n = 2 (Braun 1885). Morphological notes (only given divergencies after Ferguson & Jones 1940; Plate IV: E). Body length up to 1.1mm, typical macrostomid-like caudal region without spatulation, delimited by slight gradual depressions; anterior and posterior body-end bluntly truncated. Rhabdites in bundles with 7 to 10 rods, dispersed fairly numerous over dorsal surface, relatively sparse ventrally; posterior caudal rim of rhabdites prominent. Adhesive papillae absent. Rhammite tracks absent. Ciliary tufts very long postero-laterally, 82µm, frequently single rigid cilia laterally, and short ciliary tufts anteriorly. Reproductive system. Intervesicular duct absent; the passage between the vesicles guarded by a sphincter. Proximal portion of prostatic vesicle ciliated, distal portion and proximal stylet filled with ovoidal packets of prostatic material. Sperm without Nebengeisseln. Remarks. The length of the stylet of M. orthostylum given by several authors, differs considerably: 57µm after Ferguson & Jones (1940), 61µm after Papi (1951b), 90µm after Meixner (1915), 140µm after Beklemishev (1951), and 142µm after von Hofsten (1911). Following the descriptions made by European and North American authors, distinct differencies are present between the palearctic and nearctic forms of Macrostomum orthostylum Braun. These differencies reflect not only the divergent lengths of the stylet but also other characters such as the absence of adhesive papillae, rhammite tracks, intervesicular duct and the presence of ciliary tufts around the body and presence of the ciliated proximal part of the prostatic vesicle of the neartic forms. Notwithstanding of these different characters between paleartic and nearctic specimens, I prefer to defer from establishment of a new species because of not exactly knowing if these differences are valid or if the descriptions were given incompletely or only out of focus. Shirgur (1980) detected specimens of M. orthostylum in a brackish water fish-farm, India, tolerating salinities up to 30 (cf. Ecological Account: tolerance experiments). Ecological notes. Bauchhenss (1971) reported M. orthostylum were collected in March, July, and September at temperatures ranging from 3 to 16 C. Animals carrying eggs, were observed in July. Food: diatoms. Macrostomum parmum Ball, 1977 (Plate XI: N) Type locality. Sandy Bay, St.Helena South, St. Helena; leg. 11 Jan. 1966; types: ZM-A (holotype), (whole mount), (paratypes). Habitat. Benthal, sandy sediment, freshwater. Morphological notes of preserved specimens. Body length up to 1.2mm by 0.6mm width, broad, shield-like (name of species), extremities rounded, transparent. Two eyes present. Rhabdites in bundles dispersed over body, 15µm in length. Rhammite tracks open at anterior margin of body. Sensory cilia, up to 8µm long, widely distributed. Reproductive system with bilateral testes and ovaries. Vasa deferentia unite to common vas deferens distending to false seminal vesicle. Intervesicular duct present. Stylet (Plate XI: N) an extended funnel with distal bend at an angle of about 90 from the main axis, 160µm long. Distal tip truncate with terminal opening; terminal thickening of wall absent. Proximal opening a = 25µm. The shaft of the stylet is straight in squash preparation, but in sections a very gentle curvature was observed. Female system composed of usal components. Oviducts inconspicuous. Cellular closure apparatus absent. Because of the poor histological condition of the specimens, the ciliation of the female atrium seemed only distally developed. Gonopore surrounded by very dense eosinophilous cement glands. Gonopores separate. 112

113 Macrostomum phillipsi Ferguson & Stirewalt, 1938 (Plate XI: *D; Tab. 1) Type locality. Pasture swamp between Barboursville and Ruckersville, Green County, Virginia, USA, NEA; types: deposition not recorded. Habitat. Swamp, freshwater. Morphological notes. Body length up to 2.0mm, macrostomid-like without pronounced waist of tail region, slender, anteriorly rounded, posteriorly truncated, colourless. Adhesive papillae absent. Adenal rhabdites, in groups of 3 to 8, occur overall the body more concentrated on anterior mid-dorsal crest and on rim of posterior body-end. Rhammite tracks arise at level of brain dividing them into dorsal and ventral groups. Numerous ciliary tufts dispersing over body. Reddish black eyes located postero-dorsal to the cerebral ganglia. Protonephridia with bilateral stems, excretory pore of which not located. Mouth laterally bounded by mucous glands pouring their products into the pharynx simplex Reproductive system with bilateral testes and ovaries. Proximally, the seminal vesicle is ciliated at inlet of sperms, receiving a short common vas deference dividing proximally into vasa deferentia. Prostatic vesicle with ciliated duct. Stylet, 65µm long, a slender funnel with deeply crenated base and distal gradually curved end; the oblique terminal opening lies on the convexe side. Sperm with two setae. Female system composed of usual components and morphology. Gonopores separate. Macrostomum phocurum Marcus, 1954 (Plates IV: O, IX: J) Type locality. Mouth of river Perequê, Island of São Sebastião, Bay of Santos, Brazil, leg. Nov. 1952; types: unknown. Habitat. Littoral benthal, muddy substrate of Mangrove belt smelling of hydrogen sulphide, freshwater, oligohaline. Morphological notes (Plate IV: O). Body length up to 1.5mm by 0.3mm width, anterior end roundish, posterior end extended to 2 lappets, at the tip of which cyanophilous glands open to the exterior and the margins are provided with adhesive glands. Dark intensive chestnut pigment is distributed in the fore-body between brain and anterior margin; cerebral area free of pigment; from brain posteriad the dorsal surface is speckled with less intensive chestnut pigment up to 3 quarter of the body. Eyes, rhabdites and track of rhammites present; rhammite track opens frontally to the exterior with single pore, the glands of which lie lateral of the pharynx. Reproductive system with separate gonopores. Bilateral testes and ovaries present. Male stylet spirally twisted and obliquely truncated at its end. The proximal stylet encases less than the half of the prostatic vesicle, the glands of which extra-vesicular. The intervesicular duct is reinforced by a slightly sclerotised ring. The anterior wall of the female atrium is non-ciliated; sperms are fixed in this wall (Marcus 1954a). Macrostomum pithecusae Papi, 1959 (Plate IX: P) Type locality. Between Barano and Buonopane, Ischia, Italy, Europe; leg. 23. Oct. 1955; types: deposition not recorded. Habitat. Crenic phytal, cascade of a volcanically heated spring, freshwater. Morphological notes. Body length up to 0.75mm, macrostomid outline with rounded extremities but anterior end sometimes roundly truncated, spatulate tail with adhesive papillae, 5-6µm long, colourless, intestine gleam whitish (i.l.). Tactile cilia, up to 6.5µm long, 113

114 around anterior margin and several longer cilia of the same length along lateral margins. Adenal rhabdites in groups of 3 to 6, dispersed over dorsal body but ventrally rhabdites are concentrated at the anterior body-end, more numerous at the posterior body-end and frontal area of mouth. Rhammite tracks present. Paired eyes present. Body muscle wall structured as usual. Intestine with Minotian cells. Reproductive system with bilateral testes and ovaries. Common vas deferens distended to false seminal vesicle. The distal part of the vas deference walled with circular muscle fibres. Distinct intervesicular duct present. Stylet (Plate IX: P) extended bow-shaped funnel gradually reduced distad. Distal part of stylet spiral in different planes, terminating into sharpened tip. Distal opening oblique and terminal on the convexe side. Length of stylet d = 41.5µm; proximal opening a = 6-9µm. Female system composed of usual components and morphology. Distal half of female atrium ciliated and with rostral cellular closure apparatus. Vagina short or indistinct. Remarks. Schwank (1986) designated M. pithecusae as a true stygobiont species. Macrostomum poznaniensis Kolasa, 1973 (Plate VII: O) Type locality. Poznan Palmhouse, Poznan, Poland; types: absent. Habitat. Sandy bottom in large basin, freshwater. Morphological notes. Body length up to 1.2mm; with typical adhesive posterior end being rounded as well as anterior end; body colourless. Bristles irregularly spaced along entire margin, anteriorly somewhat shorter. Eyes just in front of mouth. Rhabdites usually occur in packets of eight. Reproductive system with bilateral testes and single ovary. Stylet (Plate VII: O) a 45µm long, slender extended funnel with proximal opening a = 6µm; tube slightly spirally twisted in different planes, with thickened wall around distal pore; distal oblique opening terminal. Female systemt incompletely observed. Gonopores separate. Macrostomum prognosticis Schmidt & Sopott-Ehlers, 1976 (Plate VI: G) Type locality. Bahía Darwin, Tower, Galapagos Islands, PSE; leg. Schmidt, Febr to March 1973; types: ZMU-G, P Habitat. Eu- and sublittoral fringe, benthal, heterogenous fine to coarse sands, marine. Morphological notes. Body length up to 0.8mm, typically macrostomid-shaped, anterior end broadly rounded, and posterior end with adhesive plate, bluntly rounded; greatest width behind mid-body, narrowing to distinct waist at level of male organs. In i.l. colour whitish, in t.l. colour greyish. Tactile bristles on anterior body-end short and on posterior body-end up to 15µm long. Rim of adhesive plate occupied with numerous adhesive papillae, up to 5µm in length. Black eyes at posterior border of brain (one specimen without eyes). Rhammite tracks, run both to anterior body-end and to the pharynx simplex; the glands of which are located latero-caudal of the pharynx. Bundles of adenal rhabdites, up to 12µm long, sparsely distributed over body surface with the exception of the anterior and posterior body-end where they are more abundant. Reproductive system with bilateral testes and ovaries. Common vas deferens enters seminal vesicle. Intervesicular duct present. Prostatic vesicle with ciliated interior and extravesicular prostatic glands. Stylet (Plate VI: G) tube-shaped, slightly narrowing to distal bend, d = 25-30µm in length; distal part of stylet bent at an angle of about 90, is distinctly grooved at the concave side. Terminal opening slightly thickened. Female copulatory system 114

115 incompletely developed. Ovary at level of last body-fourth. Vagina surrounded by a large complex of cement glands. Gonopores separate. Ecological notes. Macrostomum prognosticis settled dominantly heterogenous sediments of the beach slope of Bahía Tower on Tower island. In a very low abundance, up to 3 individuals in 100cm 3 sediment, the species occurred between -40cm and +160cm related to chart datum (mlwl) (Schmidt & Sopott-Ehlers 1976). Macrostomum pseudoobtusum Beklemishev, 1927 (Plate VIII: G) Type locality. Saline lake near Sevastopol, Black Sea, MED; leg. Dr. Dagaieva; types: unknown. Habitat. Saline lake, salinity up to 78.3, hyperhaline Morphological notes given after Beklemishev 1927a and Stylet form relatively identical with stylet of Macrostomum rhabdophorum, however, posterior body end differently developed (Beklemishev 1927a). Reproductive system. Form of stylet like that of M. rhabdophorum Beklemishev 1927 but the stylet of M. pseudoobtusum being a slender extended funnel (Plate VIII: G), is flexed more proximad at an angle between 40 to 45 from the main axis. Distal point of stylet thickened tuba-like, more triangularly formed, with subterminal opening. Macrostomum puntapiedrensis Brusa, 2006 (Plate IX: I) Type locality. Punta Piedras ( S W), Río de la Plata, Argentina, NEO; leg. 5. Dec. 2001; types: MLP, 5354 (holotype), 5555 (paratype). Habitat. Benthos, sediment consisting of Caliche-clay and mud, brackish. Morphological notes. Body length up to 0.6mm, digitiform, with blunt body-ends, posterior end somewhat macrostomid-shaped. Longer sensory and rigid cilia scarcely in anterior and posterior body. Paired eyes at posterior region of brain. Rhabdites in groups and of larger size, particularly in posterior region of body; at caudal rim of body rhabdites obviously with adhesive function. Reproductive system. Bilateral testes in anterior body half just behind pharyngeal region. The seminal vesicle passes via an intervesicular duct into a small muscular prostatic vesicle connected distally to the long tubular stylet being 119µm long (Plate IX: I). The proximal opening of the stylet is slightly broader than the distal opening; the tip of the stylet is faintly pointed and the terminal opening oblique. Male gonopore close to posterior end. Female system not completely developed. Female pore anterior to male system. Ecological notes. The environmental data at time of sampling (Dec. 2001) were running as follows: salinity 5, conductivity 9650µS, total dissolved solids (TDS) 4790mg/L, ph 9.46, O mg/L = 142%, T 33.1C. Macrostomum purpureum Reisinger & Kelbetz, 1964 (Plate VIII: A) Type locality. Crenal of Eptá Pighés, north of Lindos, Rhodos, Greece, Europe; types: deposition not recorded. Habitat. Crenal with slow current, between leaves on detritus rich sandy bottom, freshwater. 115

116 Morphological notes. Body length up to 3.0mm, Macrostomum tuba-like, juveniles yellowish white, sexually mature specimens reddish based on dark purple to carmine tinged pigment-cells dispersed in parenchyma. Spatulate tail of juveniles stronger waisted. Reproductive system with genital system concordant with M. tuba von Graff. Stylet (Plate VIII: A) a slender funnel-shaped, distad declining tube with medial hooked bend. Walls of distal point slightly thickened with terminal oblique opening. Female system unknown. Remarks. Schwank (1986) designated M. karlingi as a true stygobiont species. Macrostomum quiritium Beklemischev, 1951 (Plate VIII: B) Synonymy. Macrostomum japonicum var. quiritium Beklemischev, 1951; p , figs Type locality. Aquaria of Experimental Laboratory, Rom, Italy, Europe; leg. 1 Oct. 1927; types: deposition not recorded. Habitat. Freshwater. Geogr. distribution. EUROPE: Poland (Poznan Palmhouse) (Kolasa 1973a, Lanfranchi & Papi 1978). Morphological notes. Body length up to 3.0mm, anterior end roundish provided with sensible hairs, posterior body spatulate adhesive glands; colour of central body greenish due to gut content. Eyes black, small, in front of mouth, very close to each other. Rhabdites short, fusiform. Reproductive system with bilateral testes and ovaries. Male copulatory apparatus consisting of false seminal vesicle (vesicula seminalis spuria, Beklemishev 1951), seminal vesicle and prostatic vesicle; all three vesicles connected by a short intervesicular duct. Stylet 140µm long, straight or to some extent slightly unevenly twisted or undulated, with thickened wall around distal pore, e = 3.5µm in diameter, proximal opening a = 12µm (Plate VIII: B); pores of stylet with distal and proximal oblique opening. Length of stylet 10 times proximal width (Beklemishev 1951). Macrostomum rectum Ax, 2008 (Fig. 43, Plate VII: K) Synonymy. Macrostomum minutum Luther, 1960; p. 86 Fig. 20A. Type locality. Tvärminne, Gulf of Finland, BAL; leg. Prof. Dr. T.G. Karling 1959; types: deposition not recorded. Habitat. Sublittoral benthal, about 14m water depth on fine sand and gyttja, oligohaline. Morphological notes. With the exception of the stylet nothing is known to the morphology of the species. The stylet of tuba type is straight and short (Karling 1974, p. 44, cf. Ax 2008, p. 104); distally, the opening of the stylet is annularly thickened (Fig. 43). Fig. 43. Macrostomum rectum. Stylet after Ax Remarks (after Ax 2008, p. 104). The description of the species based on a drawing made by Karling, was erroneously implicated by Luther into the description of Macrostomum minutum. Unlike the bent stylet of M. minutum (Plate VII: K) the stylet of M. rectum is straight. 116

117 Macrostomum recurvostylum Ferguson, 1940 (Plate XI: *E) Synonymy. Macrostomum ruebushi var. recurvostylum Ferguson, 1940; p , figs Type locality. Yale Game Preserve, New Haven, Connecticut, USA, NEA; types: deposition not recorded. Habitat. Freshwater. Morphological notes. Body length up to 2.3mm by 0.8mm width as an average, two blunted ends, posterior end narrowed from behind of gut but spatulate tail not pronounced, colourless, with intestine taking on colouration when food is ingested. Rhabdites epithelial but few project just beyond the epidermis; rhabdites in groups of 7 to 10. Spines absent; few ciliary tufts space the margins; those of body-ends shorter than lateral ones; the latter 27µm in length. Eyes quite small located at posterior border of brain but not embedded in the tissue of the brain. Excretory system with two main lateral stems; opening to the exterior not observed. Mouth supplied with normal complement of mucous glands radiating from its ciliated lips. Chromosome number n = 3. Reproductive system with bilateral testes and ovaries. Common vas deferens lacking. Seminal and prostatic vesicle separated by a spincter. Prostatic vesicles without ciliation but with pit-like depressions. Stylet 96µm in length, with indentation half-way in the length of the tube, and with distal angular bend of about 45 ; opening subterminal in the hooked end. Sperm with two latero-posterior setae, 56µm long. Female genital system normally developed. Common oviduct communicates with female atrium. Gonopores separate. Macrostomum retortum Papi, 1951 (Plate XI: P) Type locality. In puddles of S. Rossore near Pisa, Italy, Europe; leg. Febr. 1951; types: deposition not recorded. Habitat. Sublittoral, phytal, freshwater. Geogr. distribution. EUROPE: Italy (Apennines: Fosso contesora) (Kolasa 1983). Morphological notes. Body length up to 1.2mm by 0.2µm width, characteristically macrostomid-shaped with anterior end roundish with bristles, posterior body spatulate with adhesive glands. Sensitive bristles all-around lateral body. Eyes behind crescent brain, very close to each other. Rhabdite bundles with 5-8 rods, 9-13µm long; rhammite tracks present. Intestine with long cilia. Reproductive system with bilateral testes and ovaries. Gonopores separate. Female system with ciliated vagina, female atrium, and proximal oviduct. Oviduct cellular with distal cells of closure ( Verschlußapparat of German authors). Female gonopore entered by cement glands. Male copulatory system with false seminal vesicle, seminal vesicle and prostatic vesicle; seminal and prostatic vesicles joined by intervesicular duct; the common vas deferens between false and true seminal vesicle surrounded by circular muscles; intervesicular duct not walled with muscles. Stylet up to 138µm long (line d = 127µm calculated after Papi 1951b, fig. 12), spirally curved with subterminal opening of 3.5µm in diameter (e) and proximal opening 20µm in diameter (a). Stylet of M. orthostylum group (Plate XI: P). Spermatozoa, thread-shaped, motile, bearing two stiff bristles at boundary between 1 st and 2 nd third, are about 70µm long. Macrostomum reynoldsi Ferguson, 1939 (Plate VIII: *C; Fig. *16; Tab. 1) 117

118 Type locality. Little Stony Creek, Giles County, Virginia, USA, NEA, leg. B.D. Reynolds, 1933; types: NMUS-W, , Habitat. Rhitral, phytal, algae, mosses covering rocks of cascades, freshwater. Morphological notes. Body length up to 1.5mm, fairly wide, macrostomid-like with acuminately pointed anterior end and rounded posterior end with adhesive papillae on the peripheral rim. Except for the brownish intestine the entire body colourless, translucent. Rhabdites in packets of 3, 4, 6 or 8. Spines at extremities (anterior 11µm long, posterior 24µm long) and single spines sparsely spacing over body surface, ranging in length from 20 to 27µm. Black eyes present. Mucous glands dispersed over entire body surface. Mouth and distal pharynx entered by radiating tracks of gland cells; these tracks extend as far caudad as mid-body. Protonephridia with bilateral stems, which join posteriorly and which contact the glandular system of the pharyngeal cavity at level of eyes. Excretory pore not observed. Chromosome number n = 3. Reproductive system with bilateral testes and ovaries. Male copulatory organ consists of two vasa deferentia, false seminal vesicles, seminal vesicle, prostatic vesicle and stylet. Intervesicular duct only represented by a set sphincter muscle fibres. Prostatic vesicle divided into five ciliated proximal chambers and granulated distal part. Stylet, 72µm long, slender, greatly curved tube with roughly crenated base and knobbed distal end containing subterminal opening. Sperm cell with two lateral setae. Female system composed of usual components. Common oviduct and cellular closure apparatus present. Gonopores separate. Macrostomum reynoldsoni Young, 1976 (Plate VIII: D) Type locality. River Mwena south of Mombasa on Lungalunga Rhoad, Kenya, ETR; leg. 17. Febr. 1972; types: BMNH-L, (holotype), (paratype). Habitat. Sublittoral phytal, freshwater. Geogr. distribution. ETR (Mombasa: Mvita) (Young 1976a). Morphological notes. Body length up to 1.5mm, extremities rounded, spatulated posterior end with adhesive glands, colourless (t.l.), whitish (i.l.). Semi-rigid bristles, up to 18µm long, single or in groups of up to 4 along lateral margin; anterior end with bristles up to 11µm long. Rhabdites scattered in groups of up to 12, though mostly 4 to 7, over entire body surface, but less abundant in tail region. Rhammite tracks present. Eyes very close together in dorso-posterior position of brain. Reproductive system with bilateral testes and ovaries. Female system as usual. Female atrium with distinct cellular closure apparatus rostrally. Vagina of medium length surrounded by cement glands. False seminal vesicle present separated from seminal vesicle by constriction. Seminal and prostatic vesicle joined by intervesicular duct. Extravesicular prostatic glands present. Stylet (Plate VIII: D) very slightly curved with distal blunt hook in one plane. Distal opening terminal, with thickened walls. Measurements: length varied from 142 to 150µm, a = 19µm, e = 5.5µm. Macrostomum rhabdophorum Beklemischev, 1927 (Plate VIII: H) Type locality. Limestone waters grown with Enteromorpha sp., near Odessa, Ukraine, Europe; types: unknown. Habitat. Limnetic, terrestrial, phytal, Enteromorpha spp., freshwater. Morphological notes. Body length 0.8mm, macrostomid-like, broadly rounded fore-end when body contracted then fore-end blunted, posterior end small and rounded without adhesive glands. Posterior body end with bilateral tracks of rhammites which empty 118

119 terminally. Anterior rhammite tracks contain smaller rhammites than the posterior ones. A complex of granular cephalic glands empty terminally just ventral to the rhammite tracks. The rest of the body lacks rhabdites and dermal glands. Bilateral eyes, each consisting of pigment granules. Specimens with single eyes or eyeless were also found. Reproductive system with bilateral testes and ovaries. Stylet slender, funnel-like, obliquely truncated proximal base (a), and distal bend from main axis; the distal part bent, is 1/5 in length. External opening (e) bluntly oval and subterminally located (Plate VIII: H). Gonopores separate. Macrostomum riedeli Ferguson, 1940 (Plate XI: *L; Tab. 1) Type locality. Arsenic Springs, Kelley Flats, Giles County, Virginia, USA, NEA; types: deposition not recorded. Habitat. freshwater. Morphological notes. Body length 0.9mm (average of 20 specimens), with distinct characteristic cephalic region and spatulate tail region, colourless. Adhesive glands on outer rim of posterior body; rhabdites developed in groups of 2 to 8, prevalent throughout the epidermis: anteriorly in groups of 5, 6, or 8, in mid-body groups of 2, 3, 5, or 8, and in posterior body single or in groups of 2, 3, 5, 6, or 8. Ciliary tufts, up to 16µm in length, space irregularly the whole margin; ciliary tufts of the posterior body with range of length from 23.8 to 34µm. Extremities of body with rigid spines in groups of 2 or 3. Eyes present. Excretory system with lateral stems, joined at mid-body level; flame cells abundant throughout the body. External opening of excretory system not observed. Mouth bordered by typical glandular ducts. An interesting rim of glands present beneath dorsal epidermis over female genital atrium. Latter glands producing short oblong granules, are smaller than those of the mouth region. Chromosome number n=3. Reproductive system with bilateral testes and ovaries. Vasa deferentia join to common vas deferens being capable of great distension to form the false seminal vesicle just posterior to gut. Seminal vesicle ciliated. Prostatic vesicle with 4 to 5 ciliated chambers. Stylet a greatly curved funnel with broad, deeply indented base; distad the stylet suffers two changes of direction, proximally, a one a half circle and farther distad a right angle bend. The gradually reduced tube at level behind proximal circle, terminates in a sharp point. Distal opening terminal and oval in shape. Average length of stylet 24µm (average of 20 specimens); range of length from 15µm to 40µm. Female system composed as usual. Paired oviducts join to common oviduct which communicates with the female atrium. Nothing was said to the closure apparatus of the female atrium. Gonopores separate. Macrostomum romanicum Mack-Firă, 1968 (Plate V: K) Synonymy. Macrostomum salinum Ax & Borkott, Type locality. Tekirghiol Lake, Romania, Europe; leg. 30 Aug. to 15. Sept. 1963; types: deposition not recorded. Habitat. Salinity range from 5 to 200,littoral lakes, mesohaline to hyperhaline. Geogr. distribution. EUROPE: France (Camarque) (Ax & Borkott 1969). Morphological notes. Body length up to 2.0mm, typically macrostomid-shaped, anteriorly truncated, posteriorly bluntly rounded. Spatulate posterior tail slightly waisted. Anterior bodyend occupied by several rigid tactile cilia. Paired eyes and rhabite bundles present. Reproductive system with bilateral testes and ovaries. Vasa deferentia join to common vas deferens which dilates to false seminal vesicle. Intervesicular duct present. Stylet (Plate V: K) 119

120 an extended funnel with distal hook turned at an angle of about 90 between this and the main axis. Distal opening subterminal. Sperm without setae. Female system composed of usual components. Female atrium non-ciliated; rostral cellular closure apparatus present. Gonopores separate. Development. Ax and Borkott (1968) reported cleavage observations. Macrostomum rostratum Papi, 1951 (Plate V : N; Tabs 4, 10) Synonymy. Macrostomum viride rostrata Papi, 1951; p , figs Macrostomum phytophilum Beklemishev, 1951; p. 35, figs Macrostomum rostratus: Ferguson 1954; p Type locality. Lake Majavajärvi, Kittilä, Finland, Europe; leg. A. Luther, 6. June 1950; types: deposition not recorded. Habitat. Phytal, lakes and ditches grown over by Nuphar sp., Stratiotes sp., Utricularia sp., and filiform algae, down to 1.5m water depth, rivers, on stones grown with algae, down to 5m water depth, freshwater, oligohaline 1-2 (Gulf of Finland). Geogr. distribution. BAL: Gulf of Finland (Finland: Pojo-Wiek, Ekenäs Stadsfjärd, Terijoki; St. Petersburg); EUROPE: Austria (Danube and tributary streams), Finland (Kittilä), Germany (Göttingen, Seeburger See, Schleswig-Holstein, Franconia, Thuringia: Jena, Mühlhausen, Bodensee: Konstanz-Staad), Great Britain (North Wales, western Midlands: lowland calcium-rich lakes), Ireland, Italy (region near Pisa); Poland (Harsz lake, Lake Zbęchy, Poznań: greenhouse), Romania (Lacul Snagov; Lacul Herastrau - Bucureşti; Filiaş; Delta of Danube: Maliuc), Russia (RU-W: St. Petersburg, RU-E: Perm; RU-S: Orenburg: Buzuluk), Spain (Cuenza: Uña) The Netherlands (Scheldt estuary: freshwater tidal areas, Ameland); EPA: Kazakhstan (Emba); Siberia (Tomsk, Pavlosk); ETR: Kenya (Nairobi: Dam at Kiserian Vallage) (An Der Lan 1962, Ax 2008, Bauchhenss 1971, Beklemishev 1951, Den Hartog 1977, Farias, Gamo & Norena 1995, Heitkamp 1979, 1981, Kaiser 1967, 1969, 1974, Kolasa 1973b, 1979, Luther 1960, Mack-Firă 1968c, Papi 1951b, 1952, 1959, Pörner 1966, Rixen 1961, Schwank 1976, Tulp 1974, Young 1970, 1973, 1976b). Morphological notes. Body length up to 1.5mm, typically macrostomid-shaped with blunt anterior end and spatulate posterior end with adhesive papillae, colourless, transparent, gut yellowish (t.l.). Tactile bristles around anterior end 20µm long, around posterior end 50µm long. Crescentic brain just before pharynx simplex. Eyes, close to each other, at caudal border of brain. Bundles of rhabdites (8-10 rods) present; rods µm long (after Papi 1951b), 6-12µm long (after Luther 1960). Reproductive system. Bilateral testes and ovaries. False seminal vesicle representing common vas deferens, short intervesicular duct present. Stylet (Plate V : N), proximally funnel-shaped, distally beak-shaped with subterminal opening on the concave side, displays one spiral turn around its axis; measurements after Papi (1959): d = 67µm, a = about 20µm; Heitkamp (1979): a = 8-28µm averaged 17µm, d = 36-77µm averaged 55µm and e = 6-10µm averaged 7.5µm (Heitkamp: all measurements were performed on species with oocytes). Length of distal stylet beyond distal opening: 17-28µm (Bauchhenss 1971); Tulp (1974): d = 63µm. Gonopores separate. Ecological notes. After Heitkamp (1979) M. rostratum could be found from Februar to November (April to October, Bauchhenss 1971) when the water-temperatures occurred between 1-30 C (8-21 C, Bauchhenss 1971). The maximum of abundance occurred between May and August (30 50 ind./m², Heitkamp 1982). The species undergoes a polyvoltine life cycle producing up to 5 generations per year; eggs were produced from March to October (Heitkamp 1979). After Bauchhenss, sexually mature animals producing eggs, appeared only from September to October. Juveniles could often be observed during winter-time. 120

121 Autecological characters. Phytophilous to phytobiont species, living in stagnant and slowly running waterbodies. According to temperature and oxygen euryplastic; substrate polyplastic; eurythermic, ph mesoplastic, calcareous content γ-oligo- to polyplastic (Pörner 1966, Kaiser 1969, Heitkamp 1979). In Lake Constance, M. rostatum, a characteristic phytobiont, settled dominantly in the Cladophora-fringe of the rocky splash zone (Schwank 1976). The individual abundances in m water depth (18 ind. / 100cm³) were thoroughly higher than in m depth (10 ind. / 100cm³). In intermittent pools close to the banks of the lake, the species was generally absent because of its long univoltine life cycle (Schwank 1976). Food. Just as M. distinguendum, M. rostratum feeds pantophagously on Chlorophyceae (diatoms, Chlorophyceae: Chlorella sp. etc.) and Thecamoeba, Ciliata, Rotifera, and offsprings of Turbellaria (Heitkamp 1982). Macrostomum ruebushi Ferguson, 1940 (Plate X: *A) Type locality. Little River, Blount County, Tennessee, USA, NEA; types: USNM-W, 20444, Habitat. freshwater. Morphological notes. Body length up to 1.7mm, oval in shape with rounded extremities, colourless. Sparse rhammite track extend from frontal margin to behind brain. Ciliary tufts, 30µm long, space irregularly lateral margin; anterior end with few tactile spines. Rhabdites tickly spread over body surface in groups of from 6 to 8. Sensory hairs grouped space irregularly the whole margin. Black eyes dorso-posterior to brain. Excretory system with lateral convoluted tubules; external, dorsal pores of each the tubule located about 240µm posterior to the level of eyes. Mouth entered by mucous glands and rhammites. Reproductive system with bilateral testes and ovaries. Vasa deferentia unite to very short vas deferens extending immediately into seminal vesicle. Seminal vesicle ciliated, joins with prostatic vesicle via intervesicular duct. Proximally, prostatic vesicle provided with four or five ciliated chambers. Accessory glands to prostatic vesicle present. Granular material is congregated into discrete spheroidal masses in the distal part of the prostate encased by the proximal part of the stylet. Stylet tall, 80µm in length, with proximal basis crenated and truncated at an oblique angle. Distally, stylet bent and sharply pointed, with terminal opening. Female genital system normally developed. Gonopores separate. Macrostomum salemensis Beltagi & El-Said, 2003 (Plate XI: S) Type locality. Pond ý near Shebin El Kanater, 25km north of Cairo, Egypt, NAF; types: BGFEASU-C, 2 (holotype), 3 (paratype). Habitat. Phytal, Eichornia crassipes (Mart.) Solms, Elodea canadensis, salinity 3.9, ph 7.3, oligohaline. Morphological notes. Body length up to 3.0mm, greatest width anterior to mid-body, anterior end bluntly pointed, posterior end spatulate with indistinct waist at level of male organs. Adhesive glands at the ventro-caudal region. In i.l. pale white, with intestine taking on brownish colouration when food ingested. Kidney-shaped brown eyes embedded dorsoposterior in brain, with crescent lens, 18µm in diameter. Brain crescent-shaped, bilobed, surrounded by a thin membrane and walled by a muscular sheath; muscular sheath consists of few inner circular fibres and outer thin longitudinal fibres. Brain gives rise to 4 pairs of nerve stems. Sensory cilia and bristles absent. Dorsally, epithelial rhabdites in large numbers at anterior and posterior body-ends. Broad rhammite tracks arise from glands at level of eyes and brain, converging to a single track at frontal end before opening to the exterior. Epidermis 121

122 with cylindrical cells containing oval nuclei. Body muscle wall developed as usual. Pharynx simplex cylindrical provided with retractor muscle fibres; gut with undulant intestinal wall. Reproductive system with bilateral testes and ovaries. Oviducts converge in mid-line of body forming a short common oviduct. The passage to the female atrium is marked by a strong sphincter and passage cells. The epithelium of the female atrium is ciliated and walled with an inner circular and an outer longitudinal muscle layer. A short ciliated vagina leads to the exterior. Two types of cement gland cells open into the vagina and around gonopore: cyanophilous coarse polygonal granules, 5.2µm long, and eosinphilous narrow rod-shaped granules, 7µm in length by 1.5µm width. The male copulatory apparatus consists of seminal and prostatic vesicle which are connected by a short intervesicular duct, and distal stylet (Plate XI: S). The vasa deferentia unit to a common vas deferens serving as false seminal vesicle. The prostatic vesicle is ventrally divided into 5 interciliary chambers by 6 groups of long cilia, each 21µm long. The dorsal part of the prostatic vesicle is filled with coarse granules, 8µm in diameter, secreted by extravesicular glands. The stylet, d = 170µm, a = 28.8µm, e = 1.5µm, is tube-shaped, slightly curved and opens subterminal. The distal end is slightly distended, 7.6µm in diameter, but without any thickenings of the wall of the tube. Macrostomum schmitti Hayes & Ferguson, 1940 (Plate XI: J) Synonymy. Macrostomum ruebushi var. schmitti Hayes & Ferguson, 1940; p , figs 1-6. Type locality. Charlotte Pike, Nashville, Tennessee, USA, NEA; leg. Oct. to Nov. 1938; types: USNM-W, Habitat. Spring fed ponds, freshwater. Morphological notes. Body length up to 1.7mm, extremities blunt or bluntly rounded, with slight gradual contrictions marking off the spatulate tail, colourless with intestine taking on colour of food content. Eyes black, at dorso-posterior border of brain. Rhabdites, 9.8 to 14.0 long, in bundles of 1 to 12, dispersed over whole body-surface but more concentrated at the extremities. Rhammite glands and tracks at anterior body-end. Semirigid spines, 25µm long, restricted to anterior cepahlic margin; tufts of sensory cilia, 30 to 50µm long, along lateral and posterior margin. Extra-pharyngeal glands present. Intestine ciliated. Excretory system with two latero-dorsal stems extending almost from one end of body to the other, connected posteriorly to male gonopore by a commissure. At level of 100 to 130µm caudal of anterior end of intestine, paired branches of the main-stems of the excretory system pass mediodorsad over intestine and end in paired dorsal openings. Reproductive system with bilateral testes and ovaries. Vasa deferentia join in common the musculary walled seminal vesicle. False seminal vesicle absent. Intervesicular duct absent but transition guarded by a sphincter. Prostatic vesicle proximally ciliated; distal portion and proximal stylet filled with bundles of prostatic glands. Stylet (Plate XI: J) a slender funnel with distal bend flexed at an angle less than 90 ; stylet proximally crenated; distal opening subterminal on the convexity curve. Measurements of stylet: a = 18.5µm, d = 62.9µm, and e = 14.1µm. Female system composed of usual components. Gonopores separate. Chromosome number n = 3. Macrostomum semicirculatum Ax, 2008 (Fig. 44, Plate XI: G) Type locality. Takase River joining Ogawara Lake with Pacific Ocean, Aomori District, Honshu, Japan, PNW; leg. Prof. Dr. Ax, Aug. 1990; types: deposition not recorded. 122

123 Fig. 44. Macrostomum semicirculatum. Stylet (after Ax 2008). Habitat. Supralittoral benthal, sandy beach, salt-marsh about 30cm above mid-water line, sand, salinity about 15, brackish water. Other specimens. PNW: Japan (Aomori District: Obuchi Pond -polyhaline pond- north of Ogawara Lake, salinity ; Takahoko Pond -oligohaline- north of Ogawara Pond, salinity 3 ) (Ax 2008). Morphological notes. Body length up to 0.7mm; eyes present. Colour of body parenchyma yellowish. Specimens live either psammobiont or are swimming freely in the water column. Reproductive system. Stylet (Fig. 44) curved semicirclelike, with proximal funnel, a = 18-21µm; distad, the diameter of the tube decreases to a minimum of 3-4µm; terminally, the diameter of the tube increases again to 5-6µm just before the stylet opens distally in a terminal pore; distal opening without thickenings. Macrostomum sensitivum Silliman, 1884 (Plate XI: B; Tab. 2) Synonymy. Macrostomum appendiculatum var. sillimani Ferguson, 1939; p , figs 6, 7b, 8. Macrostomum sillimani: Ferguson 1954; p. 143, tab. 1. Type locality. Monroe County, New York, USA, NEA; types: unknown. Habitat. Sublittoral, brackish-water, freshwater. Geogr. distribution. EUROPE: Italy (Pisa; Appennines: Fosso copntesora ), Poland (Konin lakes, Lake Zbęchy), Romania (Balta Cernica); NEA: USA (Falmouth, Massachusetts, Ontario, New York: Monroe County, Illinois: Mississippi Basin, Havana, Urbana) (Ferguson 1939a, von Graff 1911, 1913, Gregory, Hebert & Kolasa 2000, Higley 1918, Kolasa 1973a, 1979, 1982, Mack-Firă 1968c, Papi 1951b). Morphological notes. Body length up to 1.5mm, macrostomid-shaped outline with anterior end tapering to a blunt point, posterior body spatulate, maximum broadening of body behind mouth; colour in t.l. greyish-white with the exception of golden brown (yellowish and opaque in populations of Poland) intestine due to food particles. Sensory cilia 30µm long, irregularly spaced over dorsal surface (after Kolasa 1973: cilia in tufts, longest up to 90µm). Brain without usual median constriction. Small eyes dorsally with respect to the brain, colour black. Adenal rhabdites single or in bundles of two and three (after Papi 1951: up to 10 rods), 9-11µm long; rhammite glands lateral of brain, the tracks of which open frontal. Bilateral stems of protonephridia join between brain and mouth, into which the cross commissure communicates. Pharyngeal glands latero-caudal of pharynx, enter distal pharynx by radiating tracks. Ciliated intestine with regularly shaped lateral diverticula. Reproductive system with bilateral testes and ovaries. Common vas deferens and seminal vesicle walled with strong circular muscle layer; intervesicular duct absent. Stylet (Plate XI: B) straight, gradually narrowing distad to a pointed tip; terminally bent in an angle of approximately 25 ; stylet about 55µm (d) long (after Kolasa 35µm long), with subterminal pore on the convexity of the curve; proximal opening up to 15µm (a) in diameter. Macrostomum shenandoahensis Ferguson, 1940 (Plate XI: *C, Fig. *16; Tab. 1) 123

124 Synonymy. Macrostomum ruebushi var. shenandoahensis Ferguson, 1940; p , figs Type locality. New Market, Virginia, Connecticut, USA, NEA; types: USNM-W, 20446, Habitat. Fluviatile, spring brooks, freshwater. Geogr. distribution. NEA: USA (Virginia: Sugar Hollow, Albemarle County) (Ferguson 1940). Morphological notes. Body length up to 2.0mm by 0.8mm width, cigar-like shape without pronounced spatulation of rear body end, extremities bluntly rounded, colourless. Spines absent; ciliary tufts space the margins. Eyes small, at posterior border of brain. Excretory system with two main lateral stems; paired latero-dorsal openings just anterior to the testes. Chromosome number n = 3. Reproductive system with bilateral testes and ovaries. Common vas deferens absent. Short intervesicular duct present. Prostatic vesicle with proximal ciliated chambers. Granules, supplied to the prostatic vesicle, closely packed into spheroidal masses in the distal part of the prostate which is encased into the proximal part of the stylet. Stylet proximally crenated and slightly obliquely truncated, distally pointed with small lip beyond terminal opening. Spermcells about 45µm long, with two lateral setae. Female genital system composed of usual components. Gonopores separate. Macrostomum shenzhenensis (Wang, 2005) nom. n. (Plates IV: A, VIII: M) Synonymy. Macrostomum obtusa Wang, 2005; p , figs Type locality. Pond near the Pingshan Reservoir, Longgang District, Shenzhen, Guangdong Province China (22.61 N; E), EPA; leg. Dec. 2003; types: RISU-CH, SZ II -1 (holotype) SZ II (paratypes). Habitat. Phytal of pond, undersides of duckweeds, ph = 7.3, T = 22 C in Dec., freshwater. Morphological notes (Plate IV: A). Body length up to 3.15mm by 0.52µm width at level behind pharynx, Eyes kidney-shaped; distance between eyes 50µm if specimens squeezed distance up to 140µm. Rhabdites in anterior body stronger than in posterior body; bundles with 3-12 rods, 18-20µm in length. Sensory cilia in tufts, up to 3 cilia, 12-17µm long, only along anterior margin. Anterior and posterior body-end with rigid bristles; along anterior margin 12-16µm long, along posterior margin 6-7 bristles, 15-20µm in length. Reproductive system with bilateral testes and ovaries. Vasa efferentia separately join to form a common vas deferens which could strongly be distended to a false seminal vesicle when sperm production is high. Seminal and prostatic vesicle immediately connected with each other; intervesicular duct absent. Distal portion of prostatic vesicle not encased by proximal stylet (Plate VIII: M). Sclerotised stylet straight, tube-like, d = 82-91µm, a = 12-14µm, e = 3-4µm, decreases gradually distad from the proximal base. Distal opening of stylet subterminal. Diameter of the tube at level of distal opening 5-6µm; distal tip of stylet balllike, 7µm in length and 4-5µm in diameter. Remarks. Wang (2005) described Macrostomum obtusa as a new species. The species name, however, is pre-occupied by Macrostomum obtusum Vejdovsky, The new species name shenzhenensis relates to the place of finding in Shenzhen, Guangdong Province, China. Macrostomum silesiacum Kolasa, 1973 (Plate V: O) 124

125 Type locality. Szkarska Poreba, Sudety Mountains, Poland; leg. 20. Jan. 1971; types: in author s collection. Habitat. hyporheic interstitial; benthal; flooded litter of conifer needles and soil, freshwater, terrestrial. Morphological notes. Body length up to 1.1mm; anterior end broadly rounded or truncated, posterior body spatulate, stepped by a distinct waist, with adhesive papillae; delicate bristles, up to 30µm in length, irregularly spaced in tufts over body surface, at anterior margin bristles sturdy; in t.l. body transparent, in i.l. white. Eyes absent. Rhabdites occur in packets of 8-14 with a length of 11-14µm; they are most abundant and longest (24µm) in posterior part of body. Brain, mouth, pharynx, and intestine was typically found as in other species of Macrostomum. Reproductive system with bilateral testes and ovaries. Vasa deferentia join into common vas deferens which is able to distend to a false seminal vesicle. Extra-vesicular prostatic glands enter in common with intervesicular duct the prostatic vesicle. Stylet 42 56µm long (Plate V: O). Proximal opening a = 32µm, distal tube 4.2µm in diameter at level of subterminal pore; stylet funnel-like, slightly spirally twisted and distal portion bent at an angle of 90 from the main axis. Female system composed of usual components. Female pore surrounded by cement glands, leads into ciliated female atrium which is separated from the common oviduct by the cellular closure apparatus. Vagina indistinct. Gonopores separate. Macrostomum sinensis Wang, 2005 (Plate V: E, Fig. 45) Type locality. Fish pond near the Pingshan Reservoir, Longgang district, Shenzhen, Guangdong Province, China (22.61 N; E), EPA; leg. Nov. 2003; types: RISU-CH, SZ I 1 (holotype) SZ I (paratypes). Habitat. Sublittoral, T 22 C, ph 7.6, and average depth of pond 150cm, freshwater. Morphological notes (m.l.s.). Body length up to 1.76mm by 0.28mm width, anterior end bluntly pointed, posterior end waisted at last body fifth, with blunt adhesive plate, colour milky white (in i.l.). Eyes kidney-shaped; distance between eyes 35µ. Anterior and posterior body-end with rigid bristles; along posterior margin 5-8 bristles, 10-16µm in length. Rhabdites in bundles with 1-9 rods, 14-18µm long. Tufts of sensory cilia, 2-3, 10-12µm long, only along anterior margin. Reproductive system with bilateral testes and ovaries. Vasa deferentia separately join to common vas deferens. If sperm production is high, the common vas deferens distends forming a false seminal vesicle. Intervesicular duct between seminal and prostatic vesicle absent. Distal part of prostatic vesicle encased by proximal stylet. Fig. 45. Macrostomum sinensis Wang, A. Male stylet. B. distal tip of stylet (bars 5µm). Sclerotised stylet tube-like, d = µm, slightly curved in J-shape, decreases distad gradually from the proximal base, a = 40-52µm, to a pointed tip. Distally, stylet with pointed hook-like bend turned at an angel of about 90 from the main axis (Fig. 45). Epithelium of female atrium 12µm tall and provided with 8µm long cilia (m.l.s.). Vagina ciliated and surrounded with cement glands. Ecological notes. T 22 C, ph 7.6, and average depth of pond 150cm; freshwater (Wang 2005). 125

126 Macrostomum sinyaensis Young, 1976 (Plate IX: N) Type locality. Sinya River, Kenya, ETR; leg. 30. March 1972; types: BMNH-L, (holotype), (paratype). Habitat. Fluviatile, phytal, muddy sediment, freshwater. Geogr. distribution. ETR: Kenya (near Karen, Dam at Kiserian Village, diverse small ponds and rivers near Nairobi, Machakos), Nigeria (River Kubani) (Young 1976b, Mead & Kolasa 1984). Morphological notes. Body length up to 1.1mm, extremities rounded, posterior end spatulate, transparent (t.l.), whitish (i.l.). Posterior end with adhesive glands. Semi-rigid bristles, of up to 20µm long, distributed singly or in pairs sparsely over body; frontal end with bristles varying between 8 to 14µm. Rhabdites scattered all over entire body surface but sparse ventrally, rhabdite rods singly or in groups of 2 to 10 but most commonly 3 to 6. Rhammite tracks present but weakly developed. Eyes, almost round, in dorso-posterior position of brain. Epidermis with adenal rhabdite and mucous glands, latter more abundant ventrally. Basal membrane not observed. Body muscle wall with circular and longitudinal fibres; sparse diagonal fibres as well as dorso-ventral fibres present. Parenchyma vacuolarised. Epithelial lining of pharynx simplex an invagination of ventral epidermis. Pharynx with protractor and dilatator muscle fibres and surrounded radially by two types of gland cells. Intestine with outer longitudinal and inner circular muscle fibres; sparse radiating fibres extend to body muscle wall. Excretory system consists of two main coiled stems with branching excretory ducts terminating in flame cells; openings to the exterior not observed. Reproductive system with bilateral testes and ovaries. False seminal vesicle and seminal vesicle separated by a constriction. Seminal and prostatic vesicle joined by a distinct but short intervesicular duct. Extravesicular prostatic glands enter the prostatic vesicle near the intervesicular duct. Stylet (Plate IX: N) straight, 65 to 85µm long, proximal opening a = 10µm, distal oblique opening e = 3.4µm; exceptionally stylet appeared very slightly curved in few specimens. Female system composed as usual. Female atrium, ciliated, with distinct cellular closure apparatus rostrally at transition into common oviduct. Vagina present surrounded apparently by two types of glandular cells. Ecological notes. Macrostomum sinyaense thrives on a diet of Stenostomum brevipharyngeum Kepner & Carter, 1931 and S. tuberculosum Nuttycombe & Waters, In such condition, it was possible to induce egg production in culture experiments. Eggs laid, were hatched using yeast as trigger substance. The juveniles hatched, feed on Protozoa, especially, small flagellates. Half grown, then they feed on Stenostomum species. Other food was not observed. (Mead & Kolasa 1984). Macrostomum spirale Meixner nom. nud. in Ax, 1951 (Plates IV: M, XI : T; Figs 3, 7; Tabs 4, 5, 10) Type locality. Etang de Canet, Gulf of Lion, MED; leg. between 20 April and 29. May 1952; types: deposition not recorded. Habitat. Supralittoral benthal and in floating algal mats, salt-marshes, Farbstreifensandwatt (cyanophycean-sand), mud and sandy mud, dominantly in poly- and mesohalinicum. Geogr. distribution. BAL: Kattegat (Nivå Bay), Kieler Bucht (Bottsand), Flensburger Förde (Gelting Birk), Greifswalder Bodden: mouth of river Ryck near Wieck; ANE: North Sea (France: Wimereux, Ambleteuse; Belgian brackish water habitats; The Netherlands: Scheldt estuaries; North Frisian Islands: Sylt, Amrum); English Channel (region around Plymouth); MED: Gulf of Lion (Étang de Salses); PNE: Alaska (Kotzebue) (Armonies 1986, 126

127 1987, 1988a, Ax 1951a, 1960, 2008, Ax & Armonies 1990, Bilio 1964, Den Hartog 1974, 1977, Schockaert et al. 1989, Straarup 1970). Morphological notes (text of galley proof given by Meixner, cf. Ax 1951a, p. 287). With eyes; stylet, 80µm long tube, with spiral distal bend; male duct long with epithelium reinforced cuticular-like. Morphological notes (after Ax 1956a). Body length up to 1.3mm (specimen from Alaska 1.5mm, Ax & Armonies 1990, specimens from island of Sylt 1.6µm, Armonies 1987), typically macrostomid-shaped (Plate IV: M), anteriorly blunt, posterior end with spatulate tail occupied by adhesive papillae and characteristic waist at level of male organs, basic colour grey with intestine contrasting yellowish brown. Anterior margin provided with short, rigid tactile bristles. Rhabdites less densely dispersed over the body but on the posterior spatulate body-end rhabdites, 12-14µm long, more forceful and abundant. From glands located laterocaudally of pharynx simplex, two rhammite tracks crossing the tissue of brain, extend to the anterior margin where they open to the exterior; length of rods up to 15µm. Body muscle wall with circular and longitudinal muscle fibres; longitudinal cross-over muscle fibres present in both dorsal and ventral body muscle wall. Mouth and distal pharynx with normal complement of pharyngeal glands radiating into it. Pro- and retractor muscle fibers affixed to the anterior parts of the pharynx, extend antero-laterad. Intestine with Minotian cells. Food: diatoms, rotifers, oligochaetes and turbellarians (Straarup 1970). Reproductive system with bilateral testes and ovaries. Vasa deferentia join to false seminal vesicle lined with nucleate epithelium; wall of muscle fibres absent. Intervesicular duct enters in common with extra-vesicular prostatic glands the prostatic vesicle. Ejaculatory duct nonciliated. Stylet (Plate XI : T), d = µm in length, an extended funnel with distal spiral, hook-like, acute-angled bend. Increasing pressure to the preparation, i.e. flattening of the specimen by means of increasing pressure to the coverslip, presents forms of stylet as being depicted in Fig. B and C. (cf. Ax 1956, Fig. 6 E, H). Female system composed of usual components. Female atrium with epithelium, non-ciliated, distinctly increasing rostrad in its height; indistinct cellular closure apparatus present. Ciliated epithelial lining of vagina reinforced by conspicuous sclerotised network (after Ax 1951a Schlussleistennetz ). Cement glands enter distal vagina. Gonopores separate. Remarks. Schultz (1937, 1939) reported a record of a new species from the Farbstreifen- Sandwatt of Amrum, North Frisian Islands. After Ax (1951a), the sketch of the species made by Schultz, proves to be Macrostomum balticum Luther, After Meixner (correspondence by letter to Prof. A. Remane), Macrostomum balticum found in the Farbstreifen-Sandwatt of the island of Amrum, is presumably identical with M. spirale. In conjunction with the World War the Second, Meixner was not able to publish his manuscript containing the description of Macrostomum spirale found at Bottsand, Kieler Bucht. So it could be possible that Macrostomum balticum Luther, 1947 is identical in part or in total with M. spirale mentioned in Meixner 1938 (Tierwelt der Nord- und Ostsee). After Ax (1951a), however, M. balticum found at Amrum, is not identical with M. spirale nom. nud. Meixner from Bottsand, Kieler Bucht. Based on the short notes of Meixner, Ax (1956) presented a complete description of Macrostomum spirale found at the Etang de Canet, Gulf of Lion, Mediterranean Sea. Ecological notes. M. spirale is typically settling brackish areas preferring the transition zones of the supralittoral belt in cyanophycean-sand and salt-marshes (Bilio 1964, Den Hartog 1977, Armonies 1987, Straarup 1970). Macrostomum stirewalti Jones & Ferguson, 1941 (Fig. 46; Plate V: H) 127

128 Fig. 46. Macrostomum stirewalti. Male copulatory organs (after Jones and Ferguson 1941). Synonymy. Macrostomum appendiculatum var. stirewalti Jones & Ferguson 1941; p , plate I, figs 1-9. Type locality. Ponds paralleling Shore Drive near Lynnhaven Inlet, Princess Anne County, Virginia, USA, NEA, leg. E.R. Jones Febr. 1940; types: deposition not recorded. Habitat. hyporheic interstitial; benthal; flooded litter of conifer needles and soil, freshwater, terrestrial. Geogr. distribution. NEA: USA (Virginia: Norfolk, Smith Lake and Little Creek Reservoir) (Jones & Ferguson 1941). Morphological notes. Body length up to 1.5mm, colourless, dorsoventrally compressed, anteriorly truncated, posteriorly slightly spatulate, broadest at mid-body level. Sensory cilia, about 45µm long, single and in groups of two or three, space along body margins. Spines confined to terminal ends of body. Rhabdites, 13µm long, abundant, in groups of 7 to 9 overall except sub-anteriorly. Rhammites abundant, strongly developed above and below brain. Black eyes present. Pharynx abundantly supplied with latero-posteriad directed pharyngeal glands containing granules and rhammites. Gut sac-like, extensively ciliated. Excretory system with paired and separate lateral protonephridia; excretory porus just dorsal to anterior tip of testis field, terminal flame bulbs numerous. Reproductive system with paired testes and ovaries. Male system as usual; vasa deferentia unite just before entrance into the spheroidal, contractile seminal vesicle. Seminal and prostatic vesicle joined by a very short intervesicular duct (spincter). Prostatic vesicle surrounded by muscular wall, proximally supplied with ciliated chambers and distally with rosette of granuliferous gland cells extending into proximal part of the funnel-shaped stylet. Extravesicular glands absent. Stylet Macrostomum hystricinum type (Plate V: H), proximally crenate, distally attenuated and bent at about 45 angle, 50µm long (d) with proximal base a = 26µm. Opening of stylet long, subterminal and on convexe distal bend. Male pore ciliated and about 165µm distant from rear body end. Mature sperm about 26µm long, highly mobile with anteriorly located hyaline granule. Bristles absent. Female system as usual with ciliated female atrium which passes over a very short vagina into the female gonopore. The latter about 290µm distant from rear body end. Eggs greyish brown, spherical, and about 200µm in diameter. Macrostomum stylopencillum Jones in Ferguson, 1940 (Plate IX: O) Type locality. Currituck Sound, North Carolina, ANW, leg. E.R. Jones; types: deposition not recorded. Habitat. Sublittoral, phytal of eelgrass areas, brackish. Morphological notes. Body length up to 1.0mm by 0.13mm width, macrostomid-like in shape with the exception that the posterior end is unusually slender and lacks a typical waisted spatulation. Anterior end semi-acuminate. Numerous rhammite rods originate dorsolateral to the pharynx and extend via rhammite tracks frontad to empty anteriorly. Rhabdites uniformly but sparsely distributed upon the dorsal surface; less numerous ventrally; at extremities heavily concentrated. Bristles present. Brownish black eyes located dorsoposterior to the brain. Excretory system with lateral stems, not determined in detail. Digestive system composed of usual components, its morphology regular. 128

129 Reproductive system with bilateral testes and ovaries. Stylet (Plate IX: O) 64µm long, straight, gradually tapering to distal, extremely sharp point; proximal base crenated and distal opening terminal. Female system composed of usual components and regular in its morphology. Gonopores separate. Macrostomum subterraneum Rixen, 1961 (Plate VIII: E) Type locality. Selenter See, Schleswig-Holstein, Germany, Europe; leg. P. Ax, 1950; types: deposition unknown. Habitat. Sublittoral, benthal and stygal with sandy sediments, freshwater. Morphological notes. Body length up to 1.0mm, extremities rounded, posterior end spatulate with waist at level genital organs, adhesive papillae densely occupied at rim. Spines spaced irregularly around body, more densely occupied along extremities of body. Bundles of rhabdites, 5 to 10 rods, distributed over surface of body, more abundant in posterior body. Paired eyes composed of 3 to 7 tiny, reddish pigment granules. Reproductive system with bilateral testes; ovaries not observed. False seminal vesicle and intervesicular duct present. Prostatic vesicle with extra-vesicular glands. Stylet (Plate VIII: E) a bow-shaped extended funnel of tuba-type, flexed at an angle of about 90 ; total bow-shaped length 115µm; distance d = 90µm. Distal opening terminal, with tuba-like thickening. Gonopores separate. Remarks. Schwank (1986) designated M. karlingi as a true stygobiont species. Macrostomum tennesseensis Ferguson, 1940 (Plate VIII: *F) Type locality. Lake at Fountain City near Knoxville, Tennessee, USA, NEA; leg. types: USNM-W, Habitat. Sublittoral, springs, streams, freshwater. Geogr. distribution. NEA: USA (Tennessee: Whittle Springs region, South of Knoxville) (Ferguson 1940). Morphological notes. Body length averages over 3.0mm, macrostomid outline, longish oval, with slightly waisted spatulate posterior body-end and with small rounded anterior end; spatulate condition more distinct when specimens adhered to substratum by adhesive papillae. Colourless with the exception of eggs and ovaries being gray-black. Rhammite tracks present; its rods unusually small. Rhabdites very abundant; they occur in groups between 8 and 10. Sensory cilia in tufts of 3 to 5 in anterior region. Lateral body and hind body-end without spines or tufts. Eyes dorso-posterior to crescent brain. Digestive system with regular morphology; mouth guarded by usual type of glands being sparsely distributed about it. Lateral stems of excretory system present. Reproductive system with bilateral testes and ovaries. Vasa deferentia unite to form a false seminal vesicle. Transition to seminal vesicle indistinct by slight constriction. The same holds for the intervesicular duct. Prostatic vesicle without distinct ciliated chambers. Stylet averages 170µm in length, of tubular structure with widened crenated proximal base and with distal termination slightly expanded. Opening is terminal. Sperm with two setae. Female system composed of usual components. Gonopores separate. Macrostomum tenuicauda Luther, 1947 (Plate VIII: J; Tabs 1, 4, 5, 10) Type locality. Tvaerminne area, Finland, Gulf of Finland, BAL; types: deposition not recorded. 129

130 Habitat. Mid-littoral benthal, sand, gyttja, salt-marsh, network of roots and plants from Scirpus uniglumis Link, Juncus gerardi, Triglochin maritimum, Aster tripolium L., Glaux maritima etc. (see Luther 1947, p ), down to 0.5m water depth, freshwater, oligo- and mesohaline. Geogr. distribution. ANE: North Sea (The Netherlands: Scheldt estuary; Norway: Raunefjord, Lönningshamna; North Frisian Islands: Sylt); BAL: Gulf of Finland (Tvärminne area: Hangö, Lappvik, Taktom), Netherlands (Schelde); PNE: Alaska (Homer Spit, Seward). EUROPE: Germany (North Frisian Island: Sylt, Rantum; Holstein: saline marshes of Bad Oldeslohe, Thuringia: river Werra near Frankenroda) (Armonies 1986, 1987, 1988, Ax 2008, Ax & Armonies 1990, Den Hartog 1974, 1977, Kaiser 1974, Karling 1974b, Rixen 1961). Morphological notes. Body length up to 1.2mm, typically macrostomid-shaped, anteriorly bluntly truncated or bluntly rounded, posteriorly spatulated with prominent waist at level of genital organs. Rhabdites dispersed over body surface, ventrally less numerous; spatulate body end with extremely numerous large rhabdites (after Luther 1947 and 1960: rhammites 12 23µm in length, (m.f.s.). Anterior end with rhammite tracks, open along anterior margin to the exterior. Excretory system with lateral stems which open to the exterior immediately behind mouth. Pharynx with multiform system of pre- and retractor muscles and pharyngeal glands. Food particles are diatoms, rhizopods like species of Difflugia and Cyphoderia ampulla Ehrenberg, 1840, rotifers, unicellular algae, cyanophycean species of Anabena and filaments of Oscillatoria. Chromosomes n = 3. Reproductive system with bilateral testes and ovaries. False seminal vesicle present, separated from seminal vesicle by muscular constriction. Seminal and prostatic vesicle and intervesicular duct walled with circular muscle fibres. Stylet straight or very slightly curved, 66µm long (Finland), 65-75µm (Bad Oldeslohe), 62-65µm (Sylt), 55-65µm (Alaska), and distal wall asymmetrically thickened, point rounded (Plate VIII: J). Distal opening subterminal. Female system composed of usual components and regular morphology but characteristic cellular closure apparatus not observed. Female atrium distally ciliated and surrounded by cement glands. Gonopores separate. Macrostomum thermale Reisinger, 1933 (Plate IX: S: Fig. 20; Tab. 1) Synonymy. Macrostomum tuba sensu Menzel, 1925; p Type locality. Gunung Kapuran Laki, Kuripan, West Java, Indonesia, leg. 26. July 1929; types: deposition not recorded. Habitat. Thermal waters (37.4 to 45 C) of potassium salt springs, Sal=32, Chloride 16.3, flats covered with cushions of Oscillatoria sp. Morphological notes. Body length up to 1.0mm; broadly rounded at both ends of its broadened body, colourless, with exception of colouration of digestive tract. Spatulate disk absent, however, adhesive glands weakly developed. Adenal rhabdites in groups, 6-15 rods. Frontal glands, tactile bristles and black eyes present. Mouth entered by radiating ducts of pharyngeal glands. Intestine without Minotian cells. Excretory cells are not detectable in sectioned material. Reisinger infered from this that the protonephridial system is weakly developed or absent. Nervous system developed as usual. The postpharyngeal commissure strongly developed; pharyngeal nerve ring and tail ganglion proportionally weakly developed. Reproductive system with bilateral testes and ovaries. Male complex composed of usual components. Stylet (Plate IX: S) 80µm in length, slightly bow-shaped. Female system composed of ususal components and regular morphology. Female atrium with non-ciliated, syncytial lining, delicate muscular housing, and distinct rostral cellular closure apparatus. Gonopores separate. 130

131 Remarks. As to the synonymy of Macrostomum thermophilum Riedel discussed by Ferguson (1940b), see remarks on M. thermophilum. Schwank (1986) designated M. karlingi as a true stygobiont species. Macrostomum thermophilum Riedel, 1932 (Plate IX: R) Type locality. Engelskmandshavn, Disko Island, Greenland; leg. 1926; types: deposition not recorded. Habitat. Hot spring, C in winter-time, 2m above sea level, thermophilic, freshwater. Morphological notes. Body length of preserved specimen 3.0mm; macrostomid outline with cephalic region (head), paralleled mid-body margins, spatulate tail, and extremities rounded. Rhabdites in packets of 4 and 5 dorsally, ventrally lacking. Epidermis with intraepithelial nuclei. Body muscle wall with outer circular and inner longitudinal muscle fibres; dorso-ventral muscle fibres absent. Mouth and distal pharynx entered by ducts of pharyngeal glands. Intestine filled with diatoms. Parasitic protozoa dispersed in intestine and parenchyma. Reproductive system with bilateral testes and ovaries. Seminal vesicle with non-ciliated duct and very weak muscle wall, is filled with sperm and prostatic granules whereas the prostatic vesicle contains neither granular material nor prostatic glands. Stylet a slightly curved, slender funnel, 24µm in length, with terminally pointed opening (Plate IX: R). Female system with usual components and regular morphology. Female atrium ciliated, with cubical epithelium, intra-epithelial nuclei, and strong muscle wall. Gonopores separate. Remarks. Ferguson (1940b) disposed Macrostomum thermophilum into the category species dubiae based on the criteria as following: The study was made on an insufficient amount of material, only fixed material in contracted state, the habit sketch made by Steinböck (collector of the specimen) is very poor, the stylet was neither measured nor carefully drawn, and, above all, in the drawing (Fig. 14, Riedel 1932) of the sex apparatus the vesicula seminalis is shown dorsal to the female genital atrium, while the vesicula granulorum and the major portion of the genital canal, are found anterior to the female genital atrium. A generic characteristic is that the vesicula seminalis, the vesicula granulorum, and stylet embedded into the genital canal are to be found posterior to the female genital atrium. The stylet of this dubious form and that of the well described Macrostomum thermale Reisinger, 1933 resemble somewhat. The stylets are identical in their outline but differ only in their lengths: 24µm (M. thermophilum) versus 80µm (M. thermale). Based on the short characters given by Riedel (1932), the criticism made by Ferguson seems to be justified. However, in comparison of both the species, there are existing some minor morphological differences. The main difference is given in the geographic isolation (Greenland versus Indonesia) of the localities where the species were collected. Clarification of the validity of both the species could only be brought about by re-investigation. Remarks. Schwank (1986) designated M. karlingi as a true stygobiont species. Macrostomum thingithuensis Young, 1976 (Plate X: M) Type locality. River Thingithu, 3 miles north of Nkuba, at altitude of approximately 1,640m on Mt. Kenya, ETR; leg. 27. Jan. 1972; types: BMNH-L, Habitat. Littoral, fluviatile, freshwater. Morphological notes. Body rounded posteriorly and more blunt anteriorly, typical macrostomid-like with constriction posterior to female atrium, colourless (t.l.), whitish (i.l.). 131

132 Posterior end without adhesive glands. Semi-rigid bristles, single or in groups of up to 4, distributed sparsely; length of 16µm. Rhabdites sparingly scattered over entire body surface in groups of up to 8 with greater concentration on tail. Rhammite tracks absent. Eyes, almost round, in dorso-posterior position of brain. Reproductive system with bilateral testes and ovaries. False seminal vesicle and seminal vesicle separated by a very slight constriction. Seminal and prostatic vesicle joined by a distinct intervesicular duct. Extravesicular prostatic glands absent. Stylet (Plate X: M) with distinctive notch at proximal end; distal end with rounded hook-like bend turned at an angle slightly less than 90 between this and the main axis. Distal opening oblique. Measurements: average length 58µm (not d), extremities 55 to 59µm, a = 8µm, b = 8µm. Female system as usual. Female atrium with distinct cellular closure apparatus rostrally. Short vagina present. Macrostomum thursdayensis n. sp. (Fig. 47) Type locality. Beach next to harbour of Thursday Island, Queensland, Australia, Torres Strait, PCW; leg. Faubel, 12. Oct Habitat. Eulittoral benthal, 2m (sh) exposed sandy beach slope with poorly sorted coarse sands, preponderance of grain size fractions larger than Md (+SkI) prevailing, marine. Sediment parameters. 2m (hwl 6m): Md μm = φ +0.27, QDI 1.24, SkI +0.33, POM Description (m.l.s.). Body length up to 0.77mm by 0.1mm maximum width, typically macrostomid-shaped with greatest width in mid-body, terminally truncated, posterior bodyend developed as spatulate plate, in t.l. transparent with light yellowish gleam with intestine taking on colour of food content (Fig. 47A). Spatulate plate with rim of adhesive glands. Anterior end with cephalic glands. Anterior fore-body with pear-shaped glands being obviously not connected with the cephalic glands. Huge rhabdites consisting of bundles of 2 to 6 rods, only distributed in the posterior third of body. Mouth 210µm distant from anterior margin. Food diatoms, rotifers. Reproductive system with bilateral testis. Male stylet (Fig. 47B) bow-shaped, d = 58.9µm, distad tapering; proximal opening a = 6.75µm in diameter and distal pointed tip provided with lancet-shaped oval lappet, 6.75µm long (Fig. 47B). Distal opening at transition from tube to lappet. Ovaries non-existent; only voluminous ciliated female atrium present. Common genital opening. The presence of a female atrium and cement glands around the common gonopore and the absence of ovaries indicate that the specimen described is going to decompose its genital organs and give way to the senile phase of its life cycle. Remarks. Macrostomum thursdayensis sp. n. is characterised through a distal lancetshaped tip of its stylet. Based on this character, M. thursdayensis deviate from those species normally found in the genus Macrostomum. Lamellae or ear-like auricles on stylets were described from Macrostomum auriculatum Nasonov, Velamacrostomum catarractae (Gieysztor), Velamacrostomum glochistylum (Ferguson), Velamacrostomum saifunicum (Nasonov), and Velamacrostomum velastylum (Brusa). All these species are transferred to the new genus Velamacrostomum gen. n. (Fig. Mac1.9). Etymology. The specific epithet refers to the sampling locality, i.e. Thursday Island, Torres Strait, Australia. 132

133 Fig. 47. Macrostomum thursdayensis sp. n. A. Dorsal view of a slightly squashed specimen. B. Details of posterior body end. Macrostomum timavi von Graff, 1905 (Plate VIII: L) Type locality. Harbour of Duino, Gulf of Trieste, Adriatic Sea, MED; leg. Aug. 1885; types: unknown. Habitat. Brackish waters. Morphological notes. Body length up to 2.0mm, resembling Macrostomum hystricinum Beklemishev, 1951 in shape. Reproductive system bilateral testes and ovaries. Stylet 90µm long and slightly curved extended funnel. Distal part of stylet turned at an angle of about 90 between bend and main axis. Distal portion of stylet with distended termination splitted deeply on one side. Sperms pointed at both ends and 100µm long. Remarks. V. Graff (1905) presented a very short description. The validity of the species is based on the characteristic oultine of the distal portion of the stylet. Macrostomum troubadicis Schmidt & Sopot-Ehlers, 1976 (Plate IX: T) Type locality. Bahía Academy, Santa Cruz, Galapagos Islands, PSE; leg. Schmidt, Febr to March 1973; types: deposition not recorded. Habitat. Eu- and sublittoral, benthal with sandy sediments, marine. Morphological notes. Body length up to 0.4mm, with macrostomid outline, anterior end bluntly truncated, from greatest width in mid-body slightly narrowing to adhesive plate rounded. Slight constriction at level of pharynx present. Colourless (t.l.). Tactile bristles at 133

134 anterior body-end 6µm long, along lateral margins 8-10µm long, and at posterior body-end where they are more abundant, up to 14µm long. Rhammite tracks run both to anterior bodyend and to the pharynx simplex; the glands of which are located latero-caudal of the pharynx. Eyes absent. Adenal rhabdites in bundles, about 8µm in length, sparsely distributed over body surface with the exception of the adhesive plate. Reproductive system with bilateral testes and ovaries. False seminal vesicle absent. Intervesicular duct present. Prostatic vesicle not encased in proximal stylet. Stylet (Plate IX: T) tube-shaped, length d = 43µm, proximal opening a = 4-5µm. Distal part of stylet slightly S-shaped with truncated tip; diameter of terminal opening only negligibly less than proximal one. Female copulatory organs not observed; ovaries behind mid-body. Gonopores separate. Macrostomum truncatum Ferguson, 1940 (Plate XI: *K; Fig. *16; Tab. 1) Synonymy. Macrostomum ruebushi var. truncatum Ferguson, 1940; p , figs Type locality. Gilbert, Albemarle County, Virginia, USA, NEA; types: deposition not recorded. Habitat. Springfed swamp, freshwater. Morphological notes. Body length up to 1.0mm by 0.3mm width, truncated at both bodyends, mid-body widest, posterior end spatulate but not typically waisted. Body colourless except for the intestine due to ingested food and for epithelial cell-like inclusions being of a yellow-green-brown hue; inclusions ranged up to 68µm in diameter and of fine granular apperance, occur singly or in groups (cf. Macrostomum granulophorum Ferguson 1940). Epithelial rhabdites evenly distributed; they are grouped to 7, 8 and 10 rods. Rhammite tracks extend below and above commissure of brain. Spines absent; few ciliary tufts, about 16µm in length, present and more numerous at extremities. Eyes at postero-dorsal border of brain, not embedded in brain tissue. Digestive system usual, but with one significant deviation from the normal; mucous glands are supplied with granules of 1µm length and semi-lunar in shape instead of usual spherical shape. Excretory system with two main convoluting lateral stems sending branches into all parts of parenchyma; openings to the exterior not determined. Chromosome number 2n = 6. Reproductive system with bilateral testes and ovaries. Vasa deferentia join to common vas deferens; if sperm production is high then common vas deference distends to false seminal vesicle; the latter walled with faint musculature. Prostatic vesicle with ciliated chambers; prostatic glands are massed in distal portion encased in the proximal stylet. Stylet 72µm in length, with crenated base, wider mid-portion, and bow-shaped from base to hooked and sharply pointed end. Distal hook bent at an obtuse angle somewhat more than 90 between hook and main axis. Opening subterminal. Female system composed of usual components and regular morphology. Gonopores separate. Macrostomum tuba von Graff, 1882 (Figs *4, 48, Plate IV: B, VI: A; Tab. 1, 3) Synonymy. Derostoma platurus Ant. Dugès, 1828 ; p. 158, 160, pl. IV: fig. 7. Turbella platura: Ehrenberg 1831; without pagination. Macrostoma platurus: Vaillant 1890; p Macrostomum tuba var. gigas Okugawa, 1930; p , pl. III: figs 1-5 Macrostomum tubum: Hyman 1936; 14, figs 1-5. Macrostomum bulbostylum Ferguson, 1939; p , figs Macrostomum gigas: Hyman 1943; p , figs Type locality. Montpellier, France, Europe; leg. Dugès; types: unknown. 134

135 Habitat. Sublittoral of ponds, pools, lakes, rice fields, small streams, krenal, aquaria of botanical gardens, freshwater, oligohaline, saline hot springs. Geogr. distribution: cosmopolitan. EUROPE: Austria (Steiermark, near Graz), Bulgaria (Vitosha Mountains), Czechia (Brno), Finland (Helsinki: aquaria); Gulf of Finland: Tvaerminne aerea?), France (near Montpellier), Germany (aquaria and botonical gardens Berlin, Munich, Thuringia: Jena), Italy (Lombardy: Cremona; Lago Maggiore; Pisa), Poland (Warsaw: aquaria), Romania (Danube estuary: Lacul Snagov), Russia (RU-N: Bologoye), Siberia (Angara), Sweden (Stockholm: aquaria), Ukraine (L viv, Odessa), EPA: Kazakhstan (Aral Lake), Siberia (Province of Novgorod: Lake Bologoje), China (Guangdong Province: Shantou, Shaoguan, Fujian Province: Xiamen), Japan (Lake Biwa; ponds and rice-fields near Kyoto, Osaka); ETR: Kenya (river Sirimon at alt. 2330m on Mt. Kenya, river Chania ar Nyeri at altitude of 1,700m on Aberdare Mts, diverse small ponds and rivers near Nairobi), Uganda (Lake Edward near Katwe); NEA: USA (Virginia, New York: aquaria of AMNH- NY); NEO: Venezuela (Cabagua Island: marine habitat), Brazil (Rio Grande do Sul: São Leopoldo, Nova Petrópolis; Sao Paulo); AUS: Australia (NSW: Armidale, pool on campus of New England Univ., leg. Prof. K. Rohde) (Beklemishev 1927a, Ferguson 1939a, Gamo & Leal-Zanchet 2004, Hyman 1936, 1955, Kepner & Stiff 1932, Luther 1960, Mack-Firă 1968c, Marcus 1946, Menzel 1925, Okugawa 1930, Papi 1951b, 1952, Plotnikov 1905, Pörner 1966, Purasjoki 1945, Sibiriakova 1929, Steinböck 1951a, Valkanov 1926, Vialli 1926, 1927, Wang, Hu & Luo 2004, Young 1976b,). Morphological notes after Luther 1905, 1960, Hyman 1943, 1955, Kepner & Stiff 1932, Marcus & du Bois-Reymond Marcus 1957, and Young 1976b). Body length up to 3.5 mm by 1.0mm width, typically macrostomid-shaped, anteriorly blunted, bluntly rounded or broadly rounded, broadest in mid-body, posteriorly semi-spatulate with constriction at level of male gonopore, posterior end bilobed, blunted or bluntly rounded; when specimens moving freely, the posterior end is rounded and becomes spatulate and often bilobed when the specimen adheres to substratum by the adhesive glands along the posterior rim (Plate IV: B). Young (1976b): epidermis, cilia and anterior spines all 8µm in height or length. Sensory hairs sparse, indeed 2 pairs and a single hair observed. Rhammite tracks not seen. In i.l. colour whitish, sometimes with chestnut spots; pharyngeal glands purpureus or orange; in t.l. colour dirty yellowish (often senile specimens), yellowish, or light brown yellow with the exception of the colour taking on when prey is ingested. Different kinds of glands furnish adenal rhabdites, mucus, enzymes (intestine), and granular material of the prostatic vesicle (extravesicular glands). Adenal rhabdites, more numerous at extremities, in packets of 2 to 14, mostly 6 to 8, maximum length 21µm; an Fig. 48. Macrostomum tuba. Terminal exceptionally large number of rhabdites just cell complex of flame bulbs of protonephridia (after Watson et al. 1991). dorsally than ventrally. Rhammites originate in antero-subterminal; rhabdites more numerous glandular cells at area around mouth and excrete at the borders of the latter or proceed in tracks anteriad, cross the tissue of brain and extend to the anterior margin where they open to the exterior. Anterior margin with sensory bristles, 135

136 slightly set off from the adjacent region. Sensory hair-tufts, up to 17µm in length, regularly spaced over dorsal body surface. Small eyes at dorso-posterior border of brain. The visual cell, retinula, displays three regions: rhabdome, ellipsoid, and myoid; the accesspry pigment associated with the retinula is applied to the rhabdome (Kepner & Stiff 1932). Nervous system consists of brain, two ganglia with short medium commissure, circum-pharyngeal ring, and longitudinal lateral nerve stems serving posterior body. Protonephridia with lateral stems sending a short off-shoot medio-dorsally to open to the exterior just behind the mouth; opening oval and ciliated. Flame cells at terminations of fine end branches. The terminal complex consists of three cells, a terminal and two canal cells (Fig. 48). The weir consists of two rows of longitudinal ribs with a membrane of extracellular matrix between them. The perikaryon of the terminal cell extends along the flame, forming cell junctions with the internal ribs and the cytoplasmic tubes from the proximal and second canal cells (Watson et al. 1991). Mouth with subsequent pharynx simplex abnormal capacious; intestine could engulf prey as large as almost the entire animal because of its great propensity for extension of this organ. Specimens feed on Rhizopoda (Arcella sp.), Catenulida (Stenostomum sp.), Rhabdocoela, Rotifera, Naididae (Pristina sp.), Cyclopoida, and Cladocera. Chromosome number n = 3. Reproductive system with bilateral testes and ovaries. Vasa deferentia unite to form a common vas deferens which proximally expand to a thin-walled sac of changeable shape. The distal vas deferens enter the seminal vesicle. Intervesicular duct present. Prostatic vesicle with extravesicular glands. Stylet (Plate IV: A), straight to slightly arcuated flexible tube for its entire length, is gradually tapering from its proximal opening (crenate basis after Ferguson 1939a) to its distal bulbar termination. Length of stylet varies from 155 to 480µm (Luther 1960, Young 1976b) depending on body length and age; proximal opening a = 10-16µm, distal opening e = 4µm (Young 1976b). In small specimens stylets small and usually straight and not curved like those found in larger specimens (Young 1976b). Gonopores separate. Oviducts of each ovary join to form a common oviduct in which oocytes are lodged. The common oviduct communicates with the female genital atrium via a cellular closure apparatus. Female atrium lined with large columnar cells. The lumen contains sperm which adhere to the anterior closure apparatus. Eggs dark grey in immaturity and red brown in maturity. Remarks. Hyman (1943, p.) presented a very detailed description of Macrostomum gigas Okugawa and an extensive comparison and discussion of the species Macrostomum tuba v. Graff, M. gigas Okugawa, and M. bulbostylum Ferguson. The result was that the differences between all these species are very small and could only be caused either on inaccurate descriptions and drawings, for example the distal termination of the stylet (cf. Hyman 1955, p.2-3), on the lost of their curved outline if specimens will be stronger squeezed, i.e. flattened under the increasing pressure of the coverslip (cf. Luther 1947, figs 7-9 for M. finnlandensis), or on slight variations of the body because of the residence in different habitats generating divergent phenotypes. Kepner & Stiff (1932) reported our specimens differ essentially from the species as described in but one particular the penis. The authors held the American specimens found for a variety of Macrostomum tuba based on the characters as following: chitinous, distal ring of the stylet and shell and yolk droplets seem to be elaborated by each cell destined to become an oocyte. Marcus (1946) reckoned the species M. gigas described by Hyman (1943) a valid species. Marcus believed the synonymy of the Russian material (Beklemishev (1927?) indicated by Hyman, seems to be doutful, because the length of its stylet is only 15 times the width of the proximal end against times in sure M. gigas. As rhabdites are more numerous on the ends than elsewhere in our worms, the material of Sao Paulo which suits with that of New York, makes the identity of M. bulbostylum Ferguson (and M. tuba Kepner & Stiff) with M. gigas probable. 136

137 The karyotypes illustrated by Egger and Ishida (2005) of M. gigas (2n = 6) taken from idiograms from Yamamoto et al (2003) and M. tuba (2n = 6) taken from metaphase plates from Phillips (1936), warrants not a clear evidence for the existence of two distinct valid species because the morphological outline of chromosomes based on activity levels, staining methods etc., is subject to a high variabilty and the existence of 2n = 6 is a general chromosome number within the genus Macrostomum. Ecological notes. According to Ferguson (1939a, p ), Macrostomum tuba is a great predator; also cannibalism was observed. When populations of M. tuba were growing up to great abundance then there were practically none of other rhabdocoeles present. In a new formed lake in western Virgina (Giles County), M. tuba abounded to the utter exclusion of other rhabdocoeles (Ferguson 1939a). Other prey organisms are species of Rotifera, Cladocera, Cyclopoida, Naididae, and other small invertebrates, especially, larvae and juveniles. After Ruhl (1927), M. tuba spawn cocoons with at least two oocytes. After spawning juveniles could be observed 11 to 13 days later. Hatched specimens were 0.32mm long by 0.07mm width of body. The development of genital organs started about days after hatching though the growth of body length was not completed. Cocoon deposition happened about days later. Self-fertilisation is common in M. tuba. Egg production takes about two months. In the beginning of the third month, the genital organs become reduced. Total egg production per specimen amounts to eggs whereas each cocoon contains at least two eggs. The end of life is signalised about 6-8 days before. Senile animals do not feed the gut remains empty - and about 3-2 days before death animals do not move. They remain immotile on the bottom and the colour of the body changes from a yellowish brown transperancy to deep grey. In cultivation experiments, the total time of life of M. tuba varied between 73 and 93 days per individuum (Ruhl 1927). As Meixner (1915) stated for Microstomum lineare (cf. M. lineare Ecological notes), Ruhl (1927) found that all specimens of Macrostomum tuba living in mud, were eyeless. The hatchlings of which taken in culture, however, all have developed eyes. Ruhl concluded that all specimens have reduced their eyes when living in mud as an adaptation to the habitat. Menzel (1925) reported a discovery of Macrostomum tuba in hot springs, 26.7 salinity, 45 C, in Indonesia. The species was synonymised with Macrostomum thermale Reisinger. The distribution of M. tuba in marine waters from Venezuela is very doubtful as well (Luther 1960). Macrostomum uncinatum Ax, 2008 (Fig. 49, Plate V: G) Type locality. Lagoon of Takase River connecting Ogawara Lake with Pacific Ocean, Aomori District, Honshu, Japan, PNW; leg. Prof. Dr. P. Ax, 21. and 29. Aug. 1990; types: deposition not recorded. Habitat. Eulittoral benthal, sand rich in detritus between roots of Phragmites sp. and Halophytes, salinity 15 at low water, brackish water. Fig. 49. Macrostomum uncinatum. A. and C., Stylets of different specimens. B. male copulatory organ. After Ax Morphological notes. Body length up to 0.6mm; colour light yellow; eyes and rhabdites present. Reproductive system with stylet of 137

138 hystricinum type (Fig. 49); distal opening of ovoid form; d = 50µm, a = 15 19µm, e = 10-20µm. Macrostomum vejdovskyi Ferguson, 1940 (Plate IX: *L,M) Type locality. Yale Game Preserve, New Haven, Connecticut, USA, NEA, leg. Dr. T.K. Ruebush; types: deposition not recorded. Habitat. Freshwater. Geogr. distribution: NEO: Argentina (Rio de la Plata: La Matilda stream, S W (Brusa 2006). Morphological notes. Body length longer 1.7mm by 0.7mm width; typical macrostomid outline (boat-shaped) with spatulate, somewhat pointed posterior body-end slightly waisted, and with rounded anterior end. Colourless with the exception of epidermal, green-brown cells of about 27µm in diameter present as inclusions. Rhabdites, eyes, ciliary tufts chiefly confined to lateral areas, present; spines absent. Eyes embedded in the edge of the tissue of the brain. Reproductive system with bilateral testes and ovaries. Vasa deferentia communicate directly with seminal vesicle. Prostatic vesicle with ciliated chambers. Stylet (Plate IX: *L) a slightly curved, funnel-like tube, 35µm long, with crenated base and pointed end; distal opening oval and subterminal. Female system composed of usual components and morphology. Gonopores separate. Remarks. Brusa (2006) collected Macrostomum cf. vejdovskyi Ferguson associated in floating vegetation in La Matilda stream (Febr. 12, 2001). Differences to the description of Ferguson are the body length (about 1.0µm) and the length of stylet (52µm) (Plate IX: M). Rhabdites arranged in groups of 2-3 rods, are more numerous in the posterior region. The environmental data at time of sampling (Febr. 2001) were running as follows: salinity 2.5, conductivity 1171µS, total dissolved solids (TDS) 587mg/L, ph 7.94, T 27.5C. Macrostomum verbekei Marcus & Marcus, 1957 (Plate VIII: N) Synonymy. Macrostomum tuba var. verbekei Marcus & Marcus, 1957; p.29-32, figs 1-4. Type locality. Lake Kivu, Kivu, Zaire, ETR; leg. J. Verbeke, 2 Oct. 1953; types: deposition not recorded Habitat. Sublittoral phytal, on Cladophora spp., freshwater. Morphological notes. Body length up to 0.5mm by 0.25mm width, tripartite by means of constrictions, with head, broadest mid-body, and spatulate caudal plate; extremities slightly pointed. Colour yellowish grey, mainly dorsal whereas the intestine takes on quite light based on colourless food particles ingested. Adenal rhabdites dispersed densier over dorsal surface than over the ventral one. Black eyes present. At anterior body-end subterminal glands contain fine granules of secretion. Two pits flank this group of cells. Epithelium of pharynx with adenal nuclei located between muscle wall. Extra-pharyngeal glands enter distally the pharynx. Intestine with ciliated lining, contains Ciliata and shells of diatoms. Reproductive system with bilateral testes and ovaries. Vasa deferentia join to common vas deferens distended to false seminal vesicle. Intervesicular duct lined with thick muscular wall, enters in common with extra-vesicular prostatic glands the prostatic vesicle. Stylet (Plate VIII: N), µm in length, is a slightly curved, extended funnel with proximal opening a = 28 30µm and distal opening e = 5µm. Female system composed of usual components whereas the vagina is indistinct or absent. The female atrium ciliated and provided with 138

139 proximal cellular closure apparatus leading into the common oviduct; epithelial lining with adenal nuclei. Gonopores separate. Remarks. After Young (1976a), the validity of Macrostomum verbekei is very doubtful. Macrostomum virginianum Ferguson, 1937 (Plate IX; Tab. 1) Type locality. University of Virginia, USA, N America; types: USNM-W Habitat. Freshwater. Morphological notes. Body length longer than 1.0mm; macrostomid outline with rounded spatulate posterior body-end and rounded anterior end; waists at level between brain and mouth marking off the head, at level of oviducts, and somewhat posteriad a third one beyond which the spatulate plate extends. Colourless, the exception being eggs and ovaries which are gray-black. Rhammite tracks present. Epidermis with rhabdites, lateral tufts and terminal spines. Rhabdites in groups between 8 and 10 but more numerous at anterior end; single rhabdites appear in the anterior region. Ciliary tufts between 3 and 5 cilia interspersed at irregular intervals. Eyes present at dorso-posterior border of brain. Pharynx simplex provided with pharyngeal glands radiating latero-caudad. Lateral tubes of excretory system present; excretory ducts are believed to empty separately into pharyngeal cavity. Chromosome number n = 3. Reproductive system with bilateral testes and ovaries. Vasa deferentia join to common vas deferens which dilates during passage of sperm. Entrance of common vas deferens into seminal vesicle is ciliated. Seminal vesicle with muscle wall interlaced by three layers of muscel fibres. Proximal chambers of prostatic vesicle ciliated; prostatic granules occur in the distal part affixed to the stylet. Stylet, d = 62µm, of funnel-shaped outline with crenated base, proximally bent at a right angle, and slightly expanded distal termination with subterminal opening on the convex side. Stylets of 40 sexually mature specimens were measured by Ferguson according to the scheme of Fig. 18A with the range as follows: a = 5 6µm, f = 3 7µm, h = 15 5µm. In none of the specimens the flexed region has shifted from the proximal end. Sperm with two setae. Female system composed of usual components and regular morphology. Entrance of common oviduct into female atrium provided with strong sphincter; cellular closure apparatus absent. Gonopores separate. Macrostomum viride Van Beneden, 1870 (Fig. 53, Plate XI: O) Synonymy. Macrostomum viriede: Beklemishev 1922; p. 19 (lapsus linguae). Type locality. Leuven (Louvain), Belgium, EUROPE; types: unknown. Habitat. Sublittoral, fluviatile, limnocrene, swamps, phytal, within Potamogeton L., down to 0.5m water depth, freshwater. Geogr. distribution. EUROPE: Austria (Lunzer Obersee, Steiermark); Finland (Kittilä: lakes Sorettianjärvi, Immeljärvi, Lohjanjärvi), Bulgaria (Plovtiv), Sweden, Denmark, Germany (Thuringia: Jena, Saxonia: region of Neuzehnhain), Italy (Lago Maggiore), France (Lille), Latvia (Dorpat, lake Peipus), RU-E (Ural: Orenburg), RU-N (Sankt-Peterburg), Switzerland (Augustinerholzes near Basel, Brienzer See, Thuner See, Amsoldingensee, swamps near Weißenau); EPA: Siberia (Tomsk); NEO: Argentina (Rio de la Plata: Atalaya S W) (Beklemishev 1922, Braun 1885, 1894, Brusa 2006, Ferguson 1940b, Fuhrmann 1894, v. Graff 1913, Hallez 1890, Hofsten 1907, Nasonov 1926, Papi 1951b, Pörner 1966, Steinböck 1926, Valkanov 1926, Wegelin 1966). Morphological notes. Body length up to 2.0 mm by 0.5 mm width, colourless, intestine brownish green, typically macrostomid-shaped, anteriorly with truncated end, and posteriorly 139

140 with spatulate tail. Posterior spatulate tail with adhesive glands. Body provided with tactile bristles. Entire body ciliated except for the posterior rim of the adhesive disk which is supplied with adhesive papillae. Club-shaped rhabdites, in groups of 2 or 5 rods, up to 14µm long; more numerous posteriorly. Eyes with retina cells (lens after v. Graff 1913) connected to posterior border of brain. Excretory system with lateral stems, highly ramified. Excretory pores not observed. Reproductive system with bilateral testes and ovaries. Seminal vesicle coalesced for its entire length with the prostatic vesicle. Stylet (Fig. x) spirally curved in S-shape. Female system composed of usual components and regular morphology. Gonopores separate. Remarks. Brusa (2006) collected Macrostomum cf. viride associated with floating vegetation at Atalaya (Febr. 2, 2002). Differences to the description of Ferguson are the body length (about 1.0µm) and the total cover of the body with cilia. Length of stylet is 37µm and sigmoid in shape; distal opening terminal, located at the concave side of the stylet (Fig. xb). The environmental data at time of sampling were running in Febr as follows: salinity 0, conductivity 571µS, total dissolved solids (TDS) 278mg/L, ph 6.25, T 24C. Macrostomum xiamensis Wang & Lou, 2004 (Figs 19, 50, Plate V: R) Type locality. Pond in Putuo temple of Xiamen City (24 46 N; E), Fujian Provinc, China, EPA; leg. 20. April 2003; types: RISU-CH, XM-I-1 (holotype), XM-I-2-8 (paratypes). Habitat. Pond fed by montanous spring water, ph = 7.4, T = 20 C, freshwater. Fig. 50. Macrostomum xiamensis. Sperm (after Wang & Lou, Morphological notes. Body length up to 1.22mm by 0.3mm width at mid-body, macrostomid outline with rounded anterior end, posterior body-half with constriction at level of male organs, rear end bluntly rounded. In i.l. colour milky to beige; in t.l. body colourless with darkly contrasting organs. Specimens move quickly. Epidermis µm tall (m.f.s.), cilia 6-7µm long (m.f.s.). Sensory tufts of cilia, up to 4 cilia per tuft, 10-12µm in length, space around body; space between tufts 18 to 44µm. Bristles at anterior and posterior rim of body single; anterior ones 10-14µm in length, posterior bristles 8-18µm long. Eyes present. Rhabdites in bundles, 2-6 rods per bundle, distributed over body. Rhammite tracks and adhesive glands absent. Pharynx simplex with voluminous pharyngeal glands. Reproductive system with bilateral testes and ovaries. Vasa deferentia join to common vas deferens which dilates during passage of sperm forming a false seminal vesicle. Seminal and prostatic vesicle join immediately; intervesicular duct absent. Prostatic vesicle encased by proximal funnel-shaped stylet, a = 30-32µm. Distal half of stylet (Fig. 18) sickel-shaped with acute tip; distal opening subterminal at convexe side. Angle between proximal half and sickelshaped distal half about 60, stylet being slightly squashed; the angel increase to 100 when more pressure of the coverslip will be exerted. Length of stylet d = µm. Sperm (Fig. 50) with two bristles, 12µm long, and single flagella, 24µm long. Female system consisting of paired oviducts entering commonly female atrium and distal vagina. Epithelium of female atrium 10µm tall (m.f.s.) furnished with 8µm long cilia. Vagina ciliated, short, entered by cement glands. 140

141 Species incertae sedis Macrostomum album Highley, 1918 (Plate XII: Q) Type locality. Small pond, Mississippi Basin, Illinois, USA, NEA; types: deposition not recorded. Habitat. Freshwater. Morphological notes. Body length up to 2.1mm by 0.7mm width, typically macrostomidshaped, broadest at mid-body, with typically narrowing anteriad to level of pharynx simplex giving off the head region, and posteriad to hind-gut giving off the adhesive plate; body anteriorly rounded and posteriorly truncated. Eyes dark, placed near together. In t.l. transparent, colourless. Rhabdites single or grouped in 3 or 4, scattered throughout the body surface. Posterior rim of body with rigid, thicker walled, long spines being about four times the size of the body-cilia. Reproductive system with bilateral testes and ovaries. The male chitinous spicules are shorter, more simple and not so sharply pointed in comparison with other species. Remarks. Based on the very meagre description, Ferguson (1940b, p ) transferred M. album Highley to the category species dubiae though he is of the opinion Highley did not have a Macrostomum because of some errors in the description. However, according to the drawing given by Highley (1918, fig. 21), Macrostomum album is a valid species of the genus Macrostomum but because of the ignorance of the male genital system the species warrant its position in the category species incertae sedis. Macrostomum auriculatum Nasonov, 1935 (Plate XII: H) Type locality. Bight of Marituj, Lake Baikal, Siberia, leg. June to Aug. 1927; types: unknown. Habitat. Sublittoral phytal, down 5m water depth, freshwater. Geographic distribution: EPA: Siberia (Lake Baikal: Bights of Galoustinskoje and Pestschanaja, near Olchonskije Worota (Nasonov 1935). Morphological notes. Body length up to 2.0mm, grey (i.l.). Outline and morphology of body similar to Macrostomum hystricinum Beklemischev: blunt anterior end, spatulate posterior end, with eyes, rhabdoids, and rhammite tracks. Reproductive system with bilateral testes and ovaries. Stylet (Fig. x) differing from stylet of M. hystricinum through the outline of the distal tip. Tip of stylet with an ear-like auricle which is arranged perpendicularly to the distal oblique opening. Gonopores separate. Macrostomum ophiocephalum Steinböck, 1931 (Plate XII: I-J) Locality: North of Ejde, Østerø, Faroe Islands, ANE; leg. 22. June to 19. July 1928; types: deposition or preparation not recorded. Habitat. Sublittoral fringe, benthal, marine. Morphological notes. Macrostomid-shaped, with typical constriction at level of pharynx simplex giving off the head region being snail-like, and at posterior body-end giving off the adhesive plate; posterior end rounded. Eyes absent. Reproductive system. Stylet (Fig. x) represents a short, thick tube with distal bend at an oblique angle between this and the main axis. Distal opening terminal. Seminal and prostatic 141

142 vesicle separated by a more or less deep constriction according to the drawing of Steinböck (1931, Fig. 9). Remarks. As to the male and female genital system, Steinböck most inadequately described M. ophiocephalum so that an exact assignment to any of the valid species and genera is impossible (cf. Ferguson 1940b). That implies to transfer M. ophiocephalum to the category species incertae sedis. Macrostomum sp. 1 Ax, 2008 (Fig. 51A, Plate XII M) Type locality. Morgan Park, Georgetown, Winyah Bay, South Carolina, USA, ANW; leg. Prof. Dr. Ax, Okt. 1996; types: deposition not recorded. Habitat. Supralittoral benthal about 30cm above mid-water line, sand, salinity about 15, brackish water. Fig. 51. A. Macrostomum sp. 1, male copulatory apparatus. B. Macrostomum sp. 2, stylet. After Ax Morphological notes. Body length up to 1.0mm, colourless; eyes present. Reproductive system. Male copulatory apparatus with seminal and prostatic vesicle joined by a short intervesicular duct. Prostatic vesicle with extravesicular glands; prostate not encased in proximal stylet. Slightly curved stylet with distal pointed tip; slender tube of stylet with a small proximal base and a distal hook-like bend turned at an angle of about 90 from the main axis (Fig. 51A); the small proximate part of the tip is bent again; distal opening of the stylet subterminal; d = 88µm. Macrostomum sp. 2 Ax, 2008 (Fig. 51B, Plate XII N) Type locality. Morgan Park, Georgetown, Winyah Bay, South Carolina, USA, ANW; leg. Prof. Dr. Ax, April. 1995; types: deposition not recorded. Habitat. Supralittoral benthal about 30cm above mid-water line, sand, salinity about 15, brackish water. Morphological notes. Body length up to 1.0mm; eyes present. Reproductive system. Stylet, slightly undulated tube, with distal hook-like pointed tip and small proximal base (Fig. 51B); the distal hook-like bend turned at an angle of about 90 from the main axis, opening of the stylet thickened at the convexe side; d = 90µm. Macrostomum sp. Ax & Armonies, 1987 (Plate XII: E) Type locality. St. John, Manawagonish salt marsh, Passamaquoddy Bay, New Brunswig, Canada, Gulf of Maine, ANW; leg. P. Ax, 13 Aug. to 11. Sept. 1984; types not deposited. Habitat. Eulittoral, benthal with sandy and muddy sediments with cyanobacteria between Spartina sp. and Triglochin sp., salt-marsh, brackish water. Morphological notes. Body length up to 1.0mm, without any pigmentation. Paired eyes present. 142

143 Reproductive system. Stylet similar to Macrostomum burti Ax & Armonies, 1987, 68µm in length, proximal opening a = 16µm, distal opening e = 3µm. Tube evenly tapering distad. Distal flexure more moderate than that of M. burti. Macrostomum sp. Bauchhenss, 1971 (Plate XII: K) Type locality. Sphagnum area, Franconia, Germany, Europe; types: not prepared. Habitat. Phytal, swamp, freshwater. Morphological notes. Body length 1.2mm. Reproductive system. Stylet similar to Macrostomum lacustre Beklemishev, The stylet of M. sp. is distally annularly thickened compared to M. lacustre which is thickenend after Beklemishev (1951) only on the convexe side knob-like. Stylet half the length slightly bent and proximal half funnel-shaped (Fig. x). Distal opening terminal. Measurements of stylet: d = 85µm, a = 30µm. Ecological notes. The species was found at the margin of a Sphagnum swamp: ph = 6.2, T = 14 C (Bauchhenss 1971). Macrostomum sp. Jennings, 1957 Type locality. Ponds in Leeds area, England, Europe; types: unknown. Habitat. Ponds, freshwater. Morphological notes. Body length up to 3mm by 0.5mm width. Mouth and pharynx capable of great distension. Slit-like mouth opens into simple ciliated pharynx. Eosinophilic glands located in the parenchyma enter the pharynx but they are mucus-producing. Gut unbranched sac extending almost the whole body- length; the wall is made up of two kinds of cells, standing upon a thin basement membrane. The one type are columnar cells 30-40µm tall, 5-6µm broad, with basal vesicular nuclei and fine granulated cytoplasm with inclusions giving the cell a phagocytic appearance. The second type of cells are smaller, bearing a close resemblance to the sphere-cells of triclads; they are club-shaped, 15-20µm tall and 3-4µm broad distally, with the nucleus in the narrower basal region where the cytoplams is often strongly basophilic. These cells contain eosinophilic spheres. Food organisms are minute crustaceans, annelids, nematodes, rotifers and large ciliates; mucus plays no part in its capture. Reproductive system unknown. Macrostomum sp. Ax in Rixen, 1961 (Plate XII: G) Synonymy. Macrostomum spec. (cf.? karlingi Papi) Ax, 1957; p. 429, plate 1. Type locality. Harburger Elbbrücken, Elbe river, Germany, Europe; types not prepared. Habitat. Littoral beach, sandy sediments, fluviatile, freshwater. Fig. 52. Macrostomum sp. cf. vejdovskyi Ferguson. Scales = 10µm (after Brusa 2006). Morphological notes. Related with Macrostomum karlingi Papi, Reproductive system. Stylet (Fig. 11F) bowshaped, extended funnel with subterminal opening. 143

144 Macrostomum sp. (cf. M. vejdovskyi Ferguson, 1940) Brusa, 2006 (Fig. 52; Plate XII: R-S) Type locality. La Matilda stream, punta Piedras ( S; W), Rio de la Plata, Argentina; leg. F. Brusa, Febr. 12, 2001; types not prepared. Habitat. Phytal, floating vegetation, freshwater. Morphological notes. Body digitiform with rounded anterior and bluntly rounded posterior end, rear end broader than body forming an adhesive plate; lateral sides of body parallel. Terminal ends with rigid bristles, longer than body cilia. Rhabdites in bundles each containing 2-3 rods, more numerous in posterior end of body. Eyes present in front of pharynx. Reproductive system with bilateral ovaries in posterior body half. Stylet 52µm long, straight, proximally funnel-shaped and distally pointed with subterminal opening (Fig. 52). Female gonopore, anterior to male gonopore, surrounded by cement glands. Macrostomum sp. (cf. M. viride Van Beneden, 1870) Brusa, 2006 (Fig. 53; Plate XII: T-U) Type locality. River Atalaya, ( S; W), Rio de la Plata, Argentina; leg. F. Brusa, Febr. 2, 2002; types not prepared. Habitat. Phytal, floating vegetation, freshwater. Morphological notes. Body digitiform with blunt anterior and posterior end, greatest width in posterior body half at level of ovaries. Terminal ends with rigid bristles, longer than body cilia. Eyes present in front of pharynx. Reproductive system with bilateral ovaries. Male copulatory apparatus consisting of seminal vesicle, prostatic vesicle (Brusa did not mention the prostatic vesicle but obviously it is present; according to Fig. 8A, p. 861, the prostatic vesicle is encased proximally by the funnel of the stylet (Fig. 53) and 37µm long S-shaped stylet, proximally funnel-shaped, distal opening subterminal at concave side. Remarks. The morphology of the stylet is similar to that of Macrostomum viride, though the latter has the distal end more pointed than in the specimens found. Fig. 53. Macrostomum sp. cf. viride van Beneden. Scale = 10µm (after Brusa 2006). Macrostomum sp. Kolasa, 2001 (Plate XII: F) Type locality. New Haven, USA, NEA; types: not prepared. Macrostomum finnlandensis Ferguson has a sigmoidshaped stylet similar to that of the specimens studied, though a little longer (Brusa 2006, p. 858). Morphological notes. Stylet (Plate XII: F) an extended funnel with distal bent. Distal opening subterminal. Macrostomum sp. 1 Kolasa, Strayer & Bannon-O Donnell, 1987 (Plate XII: B) Type locality. Southeastern New York, USA, NEA; types: not prepared. Habitat. Freshwater. Morphological notes unknown. 144

145 Reproductive system. Stylet (Plate XII: B) looks identical to Macrostomum ruebushi Ferguson, 1940, with proximal basis evidently truncated. Distally, stylet bent at an oblique angle between this and the main axis, sharply pointed, and with terminal opening. Macrostomum sp. 2 Kolasa, Strayer & Bannon-O Donnel, 1987 (Plate XII: C) Type locality. Southeastern New York, USA, NEA; types: not prepared. Habitat. Freshwater. Morphological notes unknown. Reproductive system. Stylet (Plate XII: C) bow-shaped, extended funnel with distal sharp point. Distal opening terminal. Remarks. The stylet of Macrostomum sp. 2 Kolasa, Strayer & Bannon-O Donnel (1987) evidently belongs to the species-group Macrostomum obtusum Vejdovsky, Macrostomum sp. Marcus, 1954 (Fig. 54) Type locality. Punta Weather, Island Guafo, S; W, Chile, PSE; types: not prepared. Habitat. Littoral, beneath Sparganium (? natans L.), freshwater. Fig. 54. Macrostomum sp. Marcus. A. dorsal view, B. diagrammatic sagittal reconstruction. C. stylet. (Figs A-C after Marcus 1954b) Morphological notes. Body length up to 0.3mm by 0.12mm width. Eyes and rhabdites present. Adhesive glands at posterior rim of body. Reproductive system. Stylet of M. hystricinum type (Fig. 54); 24µm long funnel and 12µm long bow-shaped hook bent at an angle of α > 90. The opening of the ejaculatory duct is subterminal. Single oocyte reported in Fig. 9 (Marcus 1954b) but it remains open if ovary is arranged singly or bilaterally. Macrostomum sp. (Saggio n. 45) Papi, 1951 (Plate XII: D) Type locality. Lake Majavajärvi, Kittilä, Finland, Europe; leg. 27. June 1950; types: not prepared. Habitat. Littoral, beneath Sparganium (? natans L.), freshwater. Morphological notes not known. Reproductive system. Stylet bow-shaped, extended funnel with obliguely truncated distal opening. Length d = 63µm (Papi 1951b, fig. 21). Remarks. According to the stylet, this species evidently belongs to the species-group Macrostomum obtusum Vejdovsky, Macrostomum sp. (cf. M. ruebushi var. kepneri Ferguson) Therriault & Kolasa, 1999 (Plate XII: A) Type locality. Discovery Bay, Jamaica, Caribbean Sea, ASW; leg. Jan. 1990, 1992; types: not prepared. Habitat. Supralittoral rocks pools, salinity varied between and 25, marine. 145

146 Morphological notes. Body length up to 0.65mm (m.f.s.). Reproductive system. Stylet 22µm in length (d), resembles greatly the Macrostomum ruebushi-group. Macrostomum sp. Thomas & Henley, 1971 (Fig. 14) Type locality. Still water below dam of University Lake, Chapel Hill, North Carolina, USA, NEA; types: not known. Morphological notes unknown. Investigations were made only on the ultratructure of spermatozoa. Macrostomum sp. I Tyler, 1977 Type locality. Sound side, 300m from Bogue Inlet, Bogue Bank, North Carolina, USA, NEA; types: EM examinations, deposition of sections not recorded. Habitat. Sublittoral fringe, benthal, fine sand with detritus, marine. Morphological notes. Species closely related to Macrostomum hystricinum Beklemishev, Ultrastructural investigation on the adhesive organ. The adhesive organ consists of three cell types: viscid gland, releasing gland, and anchor cell. The anchor cell enwraps the distal parts of the gland necks of the viscid and releasing gland with a relatively long tubiform collar of microvilli. The collar of microvilli represents the adhesive papillae seen in microscopical observations of living specimens. Macrostomum sp. II Tyler, 1977 Type locality. Radio Island, Morehead, North Carolina, USA, NEA; types: EM examinations, deposition of sections not recorded. Habitat. Sublittoral fringe, benthal, fine sand with detritus, marine. Morphological notes. Species closely related to Macrostomum hystricinum Beklemishev, Details of the ultrastructure of adhesive organ see Macrostomum sp. I Tyler, Macrostomum sp. III Tyler, 1977 Type locality. Sound side, 300m from Bogue Inlet, Bogue Bank, North Carolina, USA, NEA; types: EM examinations, deposition of sections not recorded. Habitat. Sublittoral fringe, benthal, fine sand with detritus, marine. Morphological notes. Species closely related to Bradburia evelinae (Marcus, 1946). Details of the ultrastructure of adhesive organ see Macrostomum sp. I Tyler, Species dubiae. Macrostomum megalogastricum Pereyaslawzewa, 1893 (Plate XII: O-P) Type locality. Sevastopol, Crimea, Ukraine, Black Sea, MED; types: not prepared. Habitat. Marine. Morphological notes (Plate XII: O). Typically macrostomid-shaped, broadest at mid-body, with typical narrowing frontad from pharynx simplex giving off the head region, and posterior 146

147 constriction of hind-gut giving off the adhesive plate; extremities rounded and provided with spines and tufts of cilia. Eyes present. Reproductive system with bilateral testes. Female system unknown. Male system described inadequately. Stylet (Plate XII: P). Macrostomum setosum Schmarda, 1859 (Plate XII: L) Synonyms. Spiroclytus setosus: Diesing 1862; p Locality: Popayan, Cauca Valley, Columbia, NEO; types not prepared. Habitat. Freshwater. Morphological notes (Plate XII: L). Body length up to 2.0mm, anteriorly roundish, posterior end pointed tail-like; i.l. colour yellowish grey. Body spaced irregularly with rigid bristles. Rhabdites single or in groups of two or three distributed over body surface, most abundant at rear body-end. Obviously posterior rim of body provided with tubules of adhesive glands. Black eyes behind brain and just anterior to mouth-cleft. Gut extends into last bodythird. Reproductive system unknown. Nomina nuda Macrostomum longistylum Kepner, Ferguson & Stirewalt, 1941 Synonymy. Macrostomum longistyla Kepner, Ferguson & Stirewalt, 1941; p. 247, fig. 3d (lapsus linguae). Locality and habitat unknown. Macrostomum norfolkensis Jones & Ferguson, 1940 Remarks. Ferguson (1954) listed in Tab. I Macrostomum norfolkensis, a freshwater species from Virginia, USA. The presented reference Jones & Ferguson (1940) is invalid. The species was never described and, therefore, M. norfolkensis remains a nomen nudum. Macrostomum ojcowiensis Kolasa, 1974 Synonymy. Macrostomum ojcowiense Kolasa, 1973; p. p. 14, tab.1 (lapsus linguae). Type locality. Ojcówski Park, Poland, Europe. Geogr. distribution: EUROPE: Poland (spring of Poznan vicinity) (Kolasa 1974) Macrostomum sp. Faubel & Warwick, 2005 Type locality. Site 7, White Island, St. Martin s, Celtic Sea, ANE; leg. 12. to 16. May Habitat. Sublittoral, rockpool at mid-littoral grown with Cladophora sp., Gelidium sp., Corallina officinalis L., marine. Macrostomum sp. Gray & Rieger, 1971 Type locality. Stoupe Beck, Robin Hoods Bay,Yorkshire, England, North Sea, ANE; leg. Aug. 27 th, 1969; types: deposition not recorded. Habitat. Eulittoral benthal of an exposed sandy beach, grain size: M z φ between 1.89 and 1.96 and σi (sorting) between 0.54 and 0.55 (grain size determination after Folk 1968), marine. 147

148 Genus Antromacrostomum Faubel, 1974 Diagnosis. Macrostomidae with single ovary and bilateral testes. Testes located in the posterior body-half; longish lateral testes connected medially. Male copulatory apparatus with seminal vesicle and distal antrum masculinum; penis, cirrus and prostatic vesicle absent. Female copulatory system with vagina passing proximad into widened female atrium. Gonopores separate. Female gonopore anterior to male pore. Pharynx simplex armed with spicule-like organs. Type of the genus: Antromacrostomum armatum Faubel, 1974 Antromacrostomum armatum Faubel, 1974 (Plate XVI: G-H; Figs 11, 78, 81, 83, 91; Tabs 5,10) Type locality. Beach off old Littoral Station, List, Sylt, North Frisian Islands, North Sea, ANE; leg. May to Sept. 1972; types: ZMU-G, P Habitat. Eulittoral stygal, semi-exposed sandy beach, marine. Geogr. distribution. ANE: North Sea (North Frisian Island Sylt: saltmarsh creek) (Faubel 1977a Hellwig 1987, Hellwig-Armonies 1988). Morphological notes (Plate XVI: G). Body length up to 0.07mm, extremely flattened, barbell-shaped, anteriorly broader than posteriorly. Caudal end with adhesive plate and terminal ciliary tuft. Colourless, without eyes. Epidermis with intra-epithelial nuclei and adenal rhabdites. Cilia of dorsal surface partly reduced. Body muscle wall structured as usual; dorsoventral muscle fibres sporadically in anterior and posterior part of body. Brain central anterior to mouth; medially, brain despatches nerve cords to innervate pharynx and frontal end; laterally, brain despatches nerve cords which run subepithelially caudad. Pharynx distally armed with spicule-like organs (prostomis composita type, cf. Acoela: Anaperidae), probably modified rhabdites. Epidermis of pharnyx crossed by extra-pharyngeal glands. Reproductive system with single ovary and bilateral testes. The longish, ventro-lateral, testicular fields are linked with each other medially; from here the common vas deferens runs caudad and passes into the seminal vesicle. Male copulatory apparatus (Plate XVI: H) with seminal vesicle and distal antrum masculinum; latter lined with nucleate epithelium and bilayered muscle wall. Prostatic vesicle absent. Female apparatus with short distal vagina expanding to voluminous, ciliated female antrum. Gonopores separate. Predator on rotifers and copepod nauplii. Ecological notes. A. armatum settles semi-exposed and lentic beaches which are poor in detritus (Faubel 1976, Hellwig 1987). The population dynamic of specimens distributed on semi-exposed beaches is given in Fig. 83. Maximal numbers of specimens were found in May and June, 21 and 24 individuals totally (Fig. 83). After Hellwig (1987) most densities occurred in lentic sandy beaches: 32.5 ind. in February, annual mean 12.9 ind./10cm². The life cycle of A. armatum is given in Fig. 91. The sexual reproduction phase proceeds in spring. A. armatum developes protandrously. More information see Ecological Account. Genus Archimacrostomum Ferguson, 1954 Diagnosis. Macrostomidae with bilateral testes and ovaries. Reduced prostatic vesicle without having a proper epithelial or muscular wall; the distal ampulla-like glandular ducts encased by the proximal funnel-shaped enlargement of the stylet; the appropriate prostatic glands surround the ejaculatory duct and proximal stylet. Gonopores separate. Marine. Type of the genus: Macrostomum beaufortensis Ferguson,

149 Remarks. Species of the genus Archimacrostomum are taxonomically determined mainly after its outline and measurements of the male stylet and its absence of a true prostatic vesicle. The anatomy of the male and female genital apparatus is typically macrostomid-like and identical with most of the macrostomid species. Therefore, the genital system does not warrant a detailed description. The male system consists of ventro-lateral testes, vasa deferentia running caudad lateral of the intestine, a seminal vesicle, a reduced prostatic vesicle and a male stylet which projects into the male gonopore. The female genital complex consists of bilateral ovaries, oviducts joining to a common oviduct, female genital atrium, vagina, and distal gonopore. The vagina is distally surrounded by cement glands. Divergencies from these general morphological pattern will be described. Key to the species of Archimacrostomum. 1 without zoochlorellae in parenchyma 2 - zoochlorellae distributed in parenchyma Archimacrostomum beaufortensis 2 anterior body not characteristically pigmented 3 - anterior body with red tranverse band and red couple of pigment Archimacrostomum rubrocinctum 3 bilateral ovaries posterior to mid-body 4 - bilateral ovaries distinctly anterior to mid-body Archimacrostomum obelicis 4 caudal spatulate plate roundish 5 - caudal spatulate plate bilobed and frontal edges with ciliary tufts Archimacrostomum brasiliensis 5 rhammite tracks absent or inconsiderable 7 - rhammite tracks present 6 6 common vas deferens distended to false seminal vesicle Archimacrostomum astericis - common vas deferens absent Archimacrostomum peteraxi 7 bristles very few all-around body Archimacrostomum sublitorale - bristles very numerous all-around body Archimacrostomum pusillum Archimacrostomum beaufortensis (Ferguson, 1937) Ferguson, 1954 (Plate XIII: *A-B; Tab. 1) Synonymy. Macrostomum beaufortense Ferguson, 1937; p , figs 1-6. Type locality. Pivers Island, Beaufort, North Carolina, USA, ANW; types: USNM-W, , (paratypes). Habitat. Littoral fringe, brackish, marine. Geogr. distribution. ANW: USA (Virginia: Norfolk Peninsula, Lafayette River), ASW: Brazil (Santos Bay, Ilha das Palmas) (Ferguson & Jones 1949, Marcus 1949). Morphological notes. Body length up to 1.4mm, typically macrostomid-shaped, extremities rounded, posterior end spatulate with sensory hair tufts and adhesive glands. Zoochlorellae present in parenchyma. Colour light brown. Rhabdite bundles (8-10 rods), anterior tracks of rhammites glands present. Eyes located behind brain. Epidermis supplied with small reddishbrown inclusions; a broad transverse band of these inclusions located just anterior to mouth on the ventral side and two broad bands lateral to the mouth (in t.l.). Bilateral branches of protonephridial system join just in front of male organ; it lacks a posterior connection. Main stems with vesicles. Zoochlorellae in parenchyma and hyaline parenchymatous vesicles present. Gut extends caudad dorsal to the genital apparatuses. Chromosome number n = 3. Reproductive system with bilateral testes and ovaries. Sperm, a thin undifferentiated thread, 51µm in length. Vasa deferentia unite just at entrance into seminal vesicle. Common vas deferens absent. Intervesicular duct present. Prostatic vesicle reduced to free prostatic glands surrounding stylet and its ampulla-like glandular ducts which encased by proximal 149

150 enlargement of the stylet. Stylet (Plate XIII: B) proximally widened, greatly curved funnel with undulating basal rim; length of stylet 24µm. Distal opening of stylet on the convex side distinctly distant from the pointed tip. Gonopores separate. Archimacrostomum astericis (Schmidt & Sopott-Ehlers, 1976) comb.n. (Plate XIII: D-E) Synonymy. Macrostomum astericis Schmidt & Sopott-Ehlers, 1976; p , fig.1. Type locality. Bahía Academy north, Santa Cruz, Galapagos Islands, PSE; leg. P. Schmidt, Febr to March 1973; types: ZMU-G, P Habitat. Sub- and eulittoral benthal, sandy sediments, marine. Morphological notes (Plate XIII: D). Body length up to 0.8mm, macrostomid-shaped with rounded anterior end and rounded spatulate posterior end, yellowish white in i.l., yellowish to reddish brown in t.l. Colour comes from dermal glands distributed over body-surface. Posterior end with more than 50 adhesive glandular tubes, each up to 6µm in length. Body allaround with sensory bristles, anterior bristles up to 20µm long, posterior ones up to 35µm long; lateral semi-rigid bristles surrounded by smaller ones. Two reniform eyes present. Adenal rhabdite bundles of up to eight rods, more abundant in fore-body. In direction to pharynx, rhabdites extend in broad fields. Rhammite tracks open fan-shaped along frontal margin. Food diatoms and Foraminifera. Reproductive system with bilateral testes and ovaries. Common vas deference distended to false seminal vesicle distally separated by distinct constriction from seminal vesicle. Short intervesicular duct and extravesicular prostatic glands extend into proximal stylet; the latter encases the distal ampulla-like ducts of the extravesicular prostatic glands and the intervesicular duct. Stylet (Plate XIII: E) measurements: a = 13-16µm (10 specimens measured); distance from proximal basis of tube to apical tip 25 to 32µm (corresponding not d). Female system composed as usual. Archimacrostomum brasiliensis (Marcus, 1952) Ferguson 1954 (Plate XIII: F-G) Synonymy. Macrostomum appendiculatum brasiliensis Marcus 1952; p , 105, figs Type locality. Canal of São Sebastião, Bay of Santos, Brazil, ASW; types: deposition not recorded. Habitat. Sublittoral, benthal, sand with mud, marine. Geogr. distribution. ASW: Argentina (Bahía Blanca estuary, Playas de Arroyo Parejas y Baterías) (Bulnes 2007). Morphological notes. Body length up to 0.8mm; fore-end truncated, hind end variable in shape, either spatulate or slightly bilobed when sticking to substrate; bilobed lappets with adhesive glands but the median depression in between free of adhesive glands; whole margin irregularly spaced with longer, sensitive bristles. Fronto-lateral edges of head with ciliary tufts. Ivory-coloured, with gut taking on colour of chest nut when diatoms ingested. Forebody and hind-body with rhammite glands and tracks. Eyes and rhabdites present. Protonephridia present with excretory pores medio-lateral. Intestine filled with diatoms. Reproductive system with separate gonopores. Male complex with reduced prostatic vesicle. Intervesicular duct and ampulla-shaped glandular ducts encased by proximal enlargement of stylet. Prostatic glands encompass proximal stylet (Plate XIII: F). Stylet (Plate XIII: G) 40µm long (? d); a = 14µm; length of horizontal tip 14µm. Female system with ciliated vagina surrounded by massive glands, and small female atrium. Evidently oviduct absent. 150

151 Ecological Notes. After Bulnes (2007), Archimacrostomum brasiliensis dominantly settled the eulittoral region of sandy beach slopes in the Bahía Blanca estuary from June to November. The highest individual number mounted up to more than 90 specimens per 125cm³ in November. Archimacrostomum obelicis (Schmidt & Sopott-Ehlers, 1976) comb. n. (Plate XIII: L-M) Synonymy. Macrostomum obelicis Schmidt & Sopott-Ehlers, 1976; p , fig. 2. Type locality. Lagoon of Espumillas, James, Galapagos Islands, PSE; leg. P. Schmidt, Febr to March 1973; types: ZMU-G, P Habitat. Eulittoral, benthal with sandy sediment, marine. Geogr. distribution. PSE: Galapagos Islands (Santa Cruz : Bahía Academy) (Schmidt & Sopott-Ehlers 1976). Morphological notes (Plate XIII: L). Body length up to 2.0mm, typically macrostomidshaped, anterior end with slight constriction behind pharynx, broadly rounded, and posterior end with adhesive plate, bluntly truncated; greatest width in mid-body, distinct waist behind caudal gut. In i.l. colour whitish, in t.l. colour grey. Tactile bristles on the anterior and posterior body more abundant but longest bristles, 25-30µm, space along lateral margins. Rim of adhesive plate occupied with numerous adhesive papillae, up to 7µm in length. Black eyes at posterior border of brain. Rhammite tracks, 6 to 7, run both to anterior body-end and to the pharynx simplex; the glands of which are located latero-caudal of the pharynx. Rhammite tracks which enter the pharynx, are composed of rhammite rods with length of 4µm and 12µm. Rhammite rods of the frontal tracks are 10µm long. Bundles of rhabdites sparsely distributed over body surface with the exception of the adhesive plate where they are more abundant. Pharynx looked smaller than usual but was greatly extensible; gut ciliated. Reproductive system with bilateral testes and ovaries. Vasa deferentia join to common vas deferens which enters the seminal vesicle walled with circular muscle fibres. An intervesicular duct enters the proximal funnel of the stylet which encloses the prostatic granular ampullae. Extravesicular prostatic glands present. Stylet (Plate XIII: M) with proximal funnel (a = 16 to 50µm) and distal hook-like bend at an angle of about 90. Distal end sharply pointed with subterminal opening on the convexe side. Length of stylet measured from centre of proximal funnel tube to distal point (corresponding approximately d), varies between 35 and 50µm. Female system with ovaries anterior to mid-body, with female atrium rostrally lined with taller, non-ciliated cells, and distal ciliated vagina surrounded by cement glands. Gonopores separate. Ecological notes. Only two individuals were sampled. Specimens move vividly on substrata and are excellent swimmers in the water column. Gut was observed with diatoms, turbellarians (in particular macrostomids), and once with a halacarid specimen ingested. Specimens are believed to be very voracious. Archimacrostomum peteraxi (Mack-Firă, 1971) Faubel & Warwick 2005 (Plate XIII: C) Synonymy. Macrostomum peteraxi Mack-Fira, 1971; p , figs1-3. Type locality. Agigea, Romania, Black Sea, MED; leg. 7. Sept. 1965; types: deposition not recorded. Habitat. Sublittoral benthal and phytal, sand, stones, brackish. Geogr. distribution. MED: Black Sea (Romania: Costineşti, Vama Veche) (Mack-Firă 1971, 1974). 151

152 Morphological notes. Body length up to 1.5mm, colourless, transparent; outline macrostomid-like with rounded anterior end and spatulate, trilobed posterior end; posterior end with adhesive papillae and tactile bristles, 30-40µm long. Paired reniform eyes lie very close to each other caudal of crescent brain. Epidermis with rhabdites occurring singly or in bundles. Rhammite glands latero-caudal of pharynx, glandular ducts of which pierce brain and open at frontal margin. Reproductive system with separate gonopores. Prostatic vesicle reduced. Intervesicular duct and ampulla-shaped glandular ducts encased by proximal enlargement of stylet. Stylet (Plate XIII: C) 27-30µm long, a = 12.5µm. Female gonopore at posterior end of second bodythird. Oviducts store 1-3 oocytes. Archimacrostomum pusillum (Ax, 1951) Faubel & Warwick 2005 (Plate XIII: N-P; Figs 78, 84; Tabs 4, 5, 10) Synonymy. Macrostomum pusillum Ax, 1951; p , fig. 2. Type locality. Schilksee, Kieler Bucht, BAL; leg. July to October 1948; types: deposition not recorded Habitat. Eulittoral tidepools, eu- and polyhalinicum. Geogr. distribution. BAL: Kieler Bucht (Eckernförde, Surendorf, Schilksee, Laboe, Wendtorfer Bucht: Bottsand); Kattegat (Nivå Bay, Isefjord); ANE: North Sea (North Frisian Islands: Amrum, Sylt; Belgium: Belgian coast, brackish water habitats; Danmark: Esbjerg; Norway: Herdla), Netherlands: Scheldt estuaries); Norwegian Sea (Tromsö) ; Skagerrak (Gullmarfjord: Kristineberg); English Channel (Plymouth Sound); North Channel (Strangford Lough; MED: Gulf of Lion (Canet Plage, Étang de Salses, Étang de Lapalme); Sea of Marmara; ANW: Gulf of Maine (Canada : St Andrew) Davis Strait (Greenland: Godhavn); PNE: Alaska (Homer Spit) (Ax 1951a, 1956a, 1959, 1995, Ax & Armonies 1990, Armonies 1987, 1988, Boaden 1963, 1966, Den Hartog 1974, 1977, Hellwig 1987, Schmidt 1972a, Schockaert et al. 1989, Straarup 1970, Westblad 1953). Morphological notes (Plate XIII: N). Body length up to 0.8mm; typically macrostomidlike, anterior end rounded, posterior end spatulate with adhesive glands, all-around body with sensory bristles, terminal bristles longer than bristles along lateral body; at posterior body bristles up to 30µm long. In t.l., colour yellowish brown caused by secretory droplets of the dorsal epidermis. Rhammite tracks scarcely developed. Rhabdite rods, 6 8 per bundle and 7 8.5µm in length, most of which united to rhabdite bundles which are evenly distributed over the body; terminally rhabdites more abundant. Paired small eyes lie close to each other caudal of crescent brain. Food diatoms; after Boaden (1963) species feeds on Ophelia sp. and ostracods. Reproductive system with separate gonopores. Bilateral testes and ovaries. Testes pass into lateral vasa deferentia which unite to a false seminal vesicle; the false seminal vesicle prove to be a part of the common vas deferens which extends into the seminal vesicle. Seminal vesicle walled with spiral muscle sheath. Seminal and prostatic vesicle joined by a short intervesicular duct. Prostatic vesicle looks globular but not walled by muscle sheath; distal part of the vesicle encased by the proximal enlargement of the stylet. The proximal part of the prostate, a loose association of prostatic glands, encompasses the uppermost proximal part of the stylet. Stylet (Plate XIII: O-P) 40µm (d) long (d = 15µm after Schmidt 1972a from Tromsø, Norway) and proximal opening 18.5µm (a). Length of stylet (not d) of species from Alaska 26-27µm, a = 16-17µm, from Canada 23-25µm, a = 10-15µm (Ax & Armonies 1990), from Kieler Bucht and French Étangs 24-25µm (Ax 1951a, 1956a). Ax (1951a) recorded on some characteristic droplets within the funnel of the stylet (Plate XIII: P). These droplets do not occur constantly (Ax 2008). Female system with female atrium and distal vagina into which cement glands enter. Gonopores separate. 152

153 Remarks. The prostatic vesicle of Archimacrostomum pusillum proves to be in deed a reduced prostatic vesicle (confirmed by own observations on species sampled in sands of the Königshaven of the Island Sylt) but the process of reduction is obviously not proceeded so far as it has been occurred in the other species of the genus Archimacrostomum where the prostate is disolved into ampulla-like ducts and related extravesicular prostatic glands. In the description of Macrostomum pusillum Ax wrote: the prostatic vesicle ist kugelförmig und umfaßt mit ihren Wandungen den oberen Teil des Stiletts. The Wandungen which encompass the proximal part of the stylet correspond to the glandular ducts of the reduced prostate surrounding the stylet. According to the photograph made by Ax (Ax & Armonies 1987, p. 18, fig. 6C-D, 1990, p. 22, fig. 10A), the prostatic vesicle clearly demonstrate a reduced form. In 1974, Faubel taxonomically determined specimens found in semi-exposed beaches of the Island of Sylt, as Macrostomum pusillum Ax, Years later on, doubts arose if the specimens collected in Sylt, would be true Macrostomum pusillum Ax, Despite of several sampling surveys to the localities in May/June when the species developed full sexual maturity, none of the specimens could be reobtained to study the reproductive system again, now based on serial sections. The differences between both the species described by Ax (1951) and Faubel (1974), are very obvious. Macrostomum pusillum sensu Faubel, 1974 differs essentially from Archimacrostomum pusillum (Ax, 1951) through the single ovary, true prostatic vesicle, shape and dimensions of the stylet, positions of eyes, and ciliary tufts around lateral bristles. Ecological notes. Archimacrostomum pusillum was observed by Hellwig (1987) in several lentic habitats of the North Frisian Island Sylt. Median abundances varied between 35.9 to 108 ind./10cm². A maximum value, 357 ind./10cm², was sampled from muddy sediments of a tidal creek. The dynamic of abundance (Fig. 84) follows the seasonal development of diatom density (Asmus 1982). Diatoms are the dominant food organisms of A. pusillum. In Nivå Bay, Kattegat, the species was rather rare. Specimens preferred fine sand poor in detritus and was common in outmost part of Nivå Bay. Specimens were found from May to September. Archimacrostomum rubrocinctum (Ax, 1951) Faubel & Warwick 2005 (Plate XIII: J-K; Fig. 12) Synonymy. Macrostomum rubrocinctum Ax, 1951; p , fig. 1. Macrostomum parthenopeum Beklemishev, 1951; p , fig. 16. Inframacrostomum rubrocinctum: Ferguson, 1954; p Type locality. Bottsand, Kieler Bucht, BAL; leg. Aug. to Sept. 1949; types: deposition not recorded. Habitat. Sublittoral algae mats (swimming near suface), periphytic, seagrass belts, muds of lentic areas, on stones, brackish. Geogr. distribution. ANE: Skagerrak (Gullmarfjord: Bays of Kristineberg, Fiskebäckskil); BAL: Kattegat (Nivå Bay, Isefjord), Kieler Bucht (Flensburg, Gelting, Heiligenhafen, Laboe); MED: Tyrrhenian Sea (Gulf of Naples: Via Partenope), Black Sea (Romania: Mangalia Lake); ANW: Gulf of Maine (Canada, Passamaquoddy Bay: St. Andrews, north of Pagan Point) (Ax 2008, Ax & Armonies 1987, Beklemishev 1951, Mack-Firă 1974, Straarup 1970, Westblad 1953). Morphological notes (Plate XIII: J). Body length up to 2.5mm; typically macrostomid-like with pronounced head being anteriorly conically pointed and the transition to mid-body slightly incised at level of pharynx, posterior end spatulate with adhesive glands. Tactile 153

154 bristles along terminal ends; bristles on the posterior end longer, about 30µm in length, than on the anterior end. In t.l., colour yellow; gut contrasted yellowish brown. Characteristic head with transversal broad band of purple pigment. Caudal of eyes additional purplish pigment stripes extending backwards to mid-level of the testes; pigment consists of tiny droplets being grouped. Number and arrangement of the pigment stripes caudal of eyes could be diversified (Ax 2008, Ax & Armonies 1887, Westblad 1953). Juveniles lack the pigment droplets; the colour of the body is completely yellow. Lateral rhammite glands at level of pharynx give rise to rhammite tracks which join posterior of eyes to a common rhammite track. This common track pierces the brain; anterior to brain the rhammite track splits again into two rhammite tracks which run obliquely anteriad. Rhabdite bundles, each with rods, become 19µm in length and cover body surface densely. Paired reniform eyes caudal of crescent brain. Food: diatoms, nematodes. Reproductive system with separate gonopores. Vasa deferentia unite to false seminal vesicle; false seminal vesicle and seminal vesicle connected via common vas deferens. Seminal vesicle walled with spiral muscle sheath. Seminal and prostatic vesicle joined by a short intervesicular duct. Prostatic vesicle looks globular but not walled by muscle sheath; distal part of the prostate, the ampulla-like glandular ducts, encased by the proximal enlargement of the stylet. The proximal part of the prostate, a loose association of prostatic glands, enter in common with the intervesicular duct the proximal part of the stylet. Stylet of holotype (Plate XIII: K) 55µm long (? d), a = 30µm, stylet from Kristineberg 75µm long (Westblad 1953), and Canadian specimens 48-58µm long, a = 36µm (Ax & Armonies 1987). Female system with indistinct female atrium and distal vagina into which cement glands enter. Gonopores far distant from each other. Remarks. Macrostomum parthenopaeum Beklemishev 1951 from Naples is presumably identical to M. rubrocinctum Ax, 1951 (Beklemishev in letter, Ax & Armonies 1987). Ecological notes. Archimacrostomum rubrocinctum moves either on substrates by means of its cilia or swim freely in the water-column; however, the swimming habit diverges from the normal habit of other macrostomids, specimens rotate constantly around its longitudinal axis. After Straarup (1970) M. rubrocinctum was found in floating algal mats and now and then in sediments. The species was only found in late summer. Food items found in the intestine of the species from Nivå Bay, are diatoms and nematodes. Archimacrostomum sp. (Doe, 1982) comb. n. (Fig. 17 B) Synonymy. Small Macrostomum sp. Rieger, 1977; given in Doe 1982, p. 40. Macrostomum sp. Doe, 1982; p , figs 1-4. Type locality. White Oak River inlet, Swansboro, North Carolina, USA. Habitat.Eulittoral benthal, upper 2cm of sand at mtl, marine. Morphological notes. The description of Macrostomum sp. is only based on ultrastructural investigations of the male copulatory apparatus (Fig. 13A), i.e. stylet and prostatic vesicle. The prostatic vesicle is reduced to ampulla-like distal ducts encased by the proximal funnel of the stylet and its appropriate glands surrounding the stylet. Stylet (Fig. 17B) funnel-shaped and gradually narrowing to a distal point; its proximal opening a = 9-11µm and 2.5µm in diameter at the level where the curve begins; 17-19µm long from proximal end to beginning of curvature and approximately 13µm long from curvature to distal point. Length d of stylet approximately 31µm, taken from Fig. 4 in Doe (1982). Distal opening of ejaculatory duct subterminal on the convexe surface of stylet. The seminal vesicle immediately enters the stylet proximally. 154

155 Archimacrostomum sublitorale Faubel & Warwick, 2005 (Plate XIII: H-I) Type locality. Lawrence s Bay, St. Martin s, Celtic Sea, ANE; leg. A. Faubel, 12. to 16. May 2002; types: BMNH-L, (CD ROM and whole mount). Habitat. Eulittoral tidepools, marine. Morphological notes (Plate XIII: H). Body length up to 2.54mm, maximum width in midbody, with characteristic macrostomid-like anterior end, posterior end rounded with several prominent adhesive glands. Around margin few, very weak sensory bristles of varying length and stiffness. In t.l. greyish translucent with yellowish brown intestine. Frontal glands present reaching anterior level of brain. Glandular ducts open at the frontal tip separately. Lateral to pores of the glandular ducts, fields with dark granulations of unknown function. Very small eyes, 270µm from anterior margin of the body (ml.s.); distance between eyes 306µm (m.l.s.). Anterior margin of crescentic brain 207µm (m.l.s.) distant from anterior end. Rhabdite bundles (3-6 rods) distributed over dorsal and ventral body surface. Digestive system with pharynx simplex pierced by extrapharyngeal glands. Mouth behind brain, 390µm (m.l.s.) distant from anterior end. Male and female pore 465µm (m.l.s.) distant from each other. Reproductive system with separate gonopores. Vasa deferentia unite just before entrance into the seminal vesicle. Prostatic glands surround the proximal part of the stylet (Plate XIII: Ib), the ampulla-like distal ducts of which are encased by the proximal enlargement of the stylet representing the reduced prostatic vesicle. An intravesicular duct joins the prostate part and the seminal vesicle. The measurements of the stylet (Plate XIII: Ia) are α > 90, a = 45µm, and d = 105µm. The distal opening is subterminal on the convex side of the distal bent part. The female system could be incomplete in that, only the bilateral ovaries and the female pore could be discerned. The female pore is surrounded by cement glands. A seminal bursa, not clearly discernible, probably lies immediately caudal close to the oocyte. Genus Bradburia Faubel, Blome & Cannon, 1994 Diagnosis. Macrostomidae with bilateral testes and ovaries. Male system with accessory hook connected to tubular stylet. Female system as in Macrostomum with bursa, female atrium and vagina. Gonopores separate. Rhabdites and rhammites present. Type of the genus: Macrostomum miraculicis Schmidt & Sopott-Ehlers, 1976 Key to the species of Archimacrostomum. 1 stylet with distal hook at the subterminal opening 2 - distal hook absent Bradburia evelinae 2 accessory pointed stylet proximally affixed to the main one Bradburia australiensis - accessory hook affixed half the length of the stylet Bradburia miraculicis Bradburia miraculicis (Schmidt & Sopott-Ehlers, 1976) (Plate XIV: I) Synonymy. Macrostomum miraculicis Schmidt & Sopott-Ehlers, 1976; p , fig. 9. Type locality. South of Bahía Tortuga, Galapagos Islands, PSE; types: ZMU-G, P Habitat. Upper eulittoral benthal, coarse sand mixed with fine sand and shells, marine. Morphological notes. Body length up to 0.6mm; with characteristic outline of body reduced to spatulate tail at rear body-end. Anterior and posterior end with bristles. Spatulate end bordered with adhesive glands. Rhammites and rhabdites sparsely present; however, a 155

156 broad line of rhabdites present caudo-lateral of pharynx simplex, becoming caudad more conspicuous. In t.l. colour grey, in i.l. colour whitish. Eyes absent. Reproductive system with bilateral testes and ovaries. Posterior part of last oocyte in direct contact with seminal bursa. Bursa lined with high cells and subdivided by a stricture into two compartments whereas the proximal cavity stores sperm and the distal cavity is free of them. The inner wall of the distal cavity is undulated and sclerotically reinforced. The distal cavity, female atrium, extends into the vagina which is subdivided by cuneiformly thickened circular muscles, sphincter, into a proximal non-ciliated part and distal ciliated part. Male system with seminal and prostatic vesicle; stylet (Plate XIV: I), tube-like, 45-75µm long with proximal opening a = 13-17µm in diameter and with distal opening e = 4-5µm in diameter. Half the length of the stylet, a 20µm long accessory hook, arcuate, caudad directed, is affixed with broad basis to the main stylet. Distal stylet with circular thickening around opening from which a hook-like, pointed process proceeds. Bradburia australiensis Faubel, Blome & Cannon, 1994 (Fig. 55; Plate XIV: G-H) Type locality.bradbury s Beach, Dunwich, North Stradbroke Island, Queensland, Australia, PCW, leg. March 1992; types: QM-B G (SS); paratypes: G (SS). Habitat. Lentic eulittoral beach with medium sand (Md µm), Sal 12. Fig. 55. Bradburia australiensis. Latero-caudal zone of sperm differentiation within the testis. to the main one (Plate XIV: H). Female genital system unknown. Morphological notes (Plate XIV: G). Body length up to 2.1mm; rear body end reduced to short spatulate tail; in t.l. dirty yellow with darker parts marking the intestine, anterior and posterior ends with stiff sensory hairs and bristles. Epidermis cellular with intraepithelial nuclei and invaginated rhabdite glands; rhabdites scattered over whole body. Fore-body with rhammite tracks originating caudal of brain. Brain with median constriction that is more common to Dolichomacrostomidae. Eyes absent. Mouth some distance behind brain. Pharynx simplex short, penetrated by extra-pharyngeal glands; intestine large, covered with 10-12µm long cilia. Reproductive system with bilateral testes lying postero-lateral to the pharynx. Differentiation of spermatids given in Fig. 55. Male system with seminal and prostatic vesicle; stylet 95µm long; proximally, in a slight constriction, a 40µm long accessory stylet affixed Bradburia evelinae (Marcus, 1946) comb. n. (Plate XIV: J-K) Synonymy. Macrostomum evelinae Marcus, 1946; p , 160, pl. III: figs Type locality. Guarujá near harbour of Santos, São Paulo, Brazil, ASW; types: unknown. Habitat. Sublittoral fringe, sandy beach, marine. Geogr. distribution. ASW: Brazil (Island of São Sebastião) (Marcus 1950). Morphological notes (Plate XIV: J). Body length up to 1.5mm by 0.25mm width, outline of body typically macrostomid-like with terminal roundish adhesive end; fore-end blunt. Colourless, less transparent. Spines space irregularly along body margin; anterior end provided with sensory spines of up to 10µm in length and posterior end with spines of up to 156

157 15µm in length. Epidermis with intra-epithelial nuclei. Rhammite glands lie lateral of pharynx, the tracks of which extend to the frontal end; along frontal margin rhammites accumulate in the epidermis to large, spindle-like bodies. Eyes and rhabdites absent. Reproductive system with bilateral testes and ovaries. Intervesicular duct short, enter in common with extravesicular prostatic glands the prostatic vesicle. Stylet (Plate XIV: K) 120µm long, proximal opening a = 22µm, with distal subterminal accessory spine bent proximad at the convexe surface. From the female pore a vagina ascends dorsad to join the bichambered female atrium; proximal chamber non-ciliated, provided with ring of high cells corresponding to the closure apparatus of other macrostomids but it does not hinder the passage of sperms completely (Marcus 1946, p. 160). Vagina and distal chamber of the female atrium ciliated; epithelium of vagina with prostatic lining and depressed nuclei. Gonopores separate. Genus Bradynectes Rieger, 1971 Diagnosis. Macrostomidae with long extended body, post-cerebral mouth, and without spatulate posterior body. Rhammite tracks piercing brain. Male stylet flexed, extending into voluminous male atrium. Female atrium and vagina absent. Single testis and ovary present. Type of the genus: Bradynectes sterreri forma kristinebergensis Rieger, 1971 Key to the species of Bradynectes. 1 testis and ovary on the right side of body 2 - testis and overy on the left side of body Bradynectes sterreri Carolina form 2 vas deferens long, without sphincter 4 - vas deferens short with sphincter 3 3 seminal vesicle with proximal sphincter Bradynectes syltensis - seminal vesicle with proximal and distal sphincter Bradynectes scilliensis 4 (2: vas deferens long, without sphincter) ovary caudal of testis and between vas deferens and body muscle wall 5 - ovary between testis and gut Bradynectes scheldtensis - male atrium lined with glandular epithelium only in the uppermost proximal part Bradynectes sterreri Robin Hood s Bay form - distal half of male atrium lined with cilia, proximal half only glandularly lined Bradynectes sterreri Bradynectes sterreri Rieger, 1971 (Kristineberg form) (Plate XIV: A; Fig ; Tabs 5, 6, 10) Type locality. Kristineberg, Gullmarfjord, Skagerrag, ANE; leg. W. Sterrer, 24. Sept ; types : AMNH-NY, Habitat. Sublittoral benthal, clean to muddy sand, down to 60cm water depth, marine. Geogr. distribution. ANE: North Sea (Belgian cost) (Schockaert et al 1989). Morphological notes (Plate XIV: A). Body length up to 2.0mm by 0.1mm width between mouth and rear body-end, slender, elongate, anterior body-end bluntly pointed. Hind end rounded with adhesive glands and sensory bristles; spatulate body-end absent. In t.l. colour brownish to yellowish based on intestine taking on colour of food content. Eyes absent. Epidermis with intra-epithelial nuclei and adenal bundles of rhabdites; basal membrane indistinct. Body muscle wall composed as usual. Rhammite glands and pharyngeal glands at both sides of pharynx simplex extending backwards to level of testis. Rhammite tracks run frontad, piercing brain and open along frontal margin. Lateral nerve stems run subepithelially caudad outside of the circular muscle layer of the body muscle wall; lateral nerve stems unite 157

158 in caudal ganglion. Pharyngeal nerve ring just above mouth. Two kinds of rhabdite glands outpour in pharyngeal gland ring. Epithelium of pharynx and intestine with intra-epithelial nuclei; intestine ciliated and surrounded with several muscle fibres. Reproductive system with single testis and ovary on the right side. Sperm averaged 64µm long; nucleus averaged 20µm long. Vas deferens extends caudad into the seminal vesicle. Seminal vesicle lined with thin, nucleate epithelium and walled with strong circular muscle layer; epithelium with long, faint cilia. Seminal and prostatic vesicle joined by intervesicular duct, 40-60µm long (m.f.s.); intervesicular duct evidently not walled with muscle sheath. Prostatic vesicle directed rostrad, surrounded with thin muscle wall; prostatic glands extravesicular. Distally, the prostatic vesicle is encased by the funnel-shaped proximal base of the stylet. Stylet (Plate XIV: A) hooked, proximally funnel-shaped, and distally with subterminal opening on the convex surface; distance between distal and proximal opening of the convex boundary (x) averaged 19µm, distance of the concave boundary (k) averaged 21µm. Stylet extends into male atrium; distal part of male atrium provided with cilia and proximal part lined with glandular epithelium, cilia lacking. Bradynectes sterreri Rieger, 1971 (Carolina form) (Plate XIV: B) Type locality. Off Beaufort, N W; North Carolina, USA, ANW; leg. April 1970; types: AMNH-NY, 744. Habitat. Sublittoral benthal, medium to coarse sand rich in detritus and mixed with shells, down to 28m water depth, marine. Morphological notes (given only differences to Kristineberg form). Body length up to 1.2mm. Bundles of rhabdites less distributed than in Kristineberg form. Rhammites longer than in Kristineberg form. Posterior body-end without sensory bristles. Reproductive system with single testis and ovary lying on left body-side. Sperm averaged 68µm long; nucleus averaged 30µm long. Distance between distal and proximal opening of convex boundary (x) of stylet averaged 31µm and of concave boundary (k) averaged 32µm. Male atrium exclusively lined with glandular epithelium; cilia absent. Bradynectes sterreri Rieger, 1971 (Robin Hood s Bay form) (Plate XIV: C) Type locality. Stoupe Beck Sand, Robin Hood s Bay, Yorkshire, North Sea, ANE; leg. Aug ; types : AMNH-NY, 745. Habitat. Sublittoral fringe to mid-eulittoral (Filey Beach), benthal, fine to medium sand mixed with low fraction of detritus, 0-5cm sediment depth, marine. Morphological notes (given only differences to Kristineberg form). Body length up to 1.2µm. Posterior body-end without sensory bristles. Reproductive system with single testis and ovary on the right side. Sperm averaged 41µm long; nucleus globular 2-3µm in diameter. Distance of convex (x) side of stylet averaged 22µm and of concave (k) side averaged 25µm. Male atrium lined with glandular epithelium only in the uppermost proximal part around the entrance of the stylet. Bradynectes scheldtensis Martens & Schockaert, 1981 (Plate XIV: E) Type locality. Eastern Scheldt, The Netherlands, North Sea, ANE; leg. 24. Aug. 1979; types: deposition not recorded. Habitat. Sublittoral benthal, fine sand, 3-4m water depth, brackish. Geogr. distribution. ANE: North Sea (Belgian coast) (Schockaert et al. 1989). 158

159 Morphological notes (Plate XIV: E). Body slender, margin with adhesive papillae, more close to each other at rear body-end. Rhabdites evidently only present in the last body-fifth. Rhammite tracks present. Reproductive system with single testis and ovary on the right side; ovary between testis and gut. Vas deferens extremely short; sphincter absent. Prostatic vesicle with extra-vesicular glands. Outline of stylet (Plate XIV: E) differs from all other known species and forms. Distance of distal and proximal opening of the convex side (x) measures 24µm, distance of the concave (k) side measures 26µm. Bradynectes scilliensis Faubel & Warwick, 2005 (Plate XIV: D) Type locality. Lawrence s Bay, St. Martin s, Celtic Sea, ANE; leg. A. Faubel, 12. to 16. May 2002; types: BMNH-L, (CD ROM and whole mount). Habitat. Eulittoral benthal, sand flat at mid-tide level, medium sand with Arenicola marina (L.) burrows, marine. Morphological notes (Plate XIV: D). Body length up to 2.1mm. Outline, colour, arrangement of rhammites, rhabdites, and posterior adhesive papillae of the body correspond to the descriptions of the phena of Bradynectes sterreri given by Rieger (1971a). Eyes, tactile cilia and adhesive glands along lateral sides and head are absent. Reproductive system with single testis and ovary on the right side. Vas deferens 80µm long (m.l.s.) turning into seminal vesicle. Distally and proximally to the seminal vesicle, strong sphincters present. Intervesicular duct enters prostatic vesicle from caudal. Distally, prostatic vesicle encased in the proximal part of the stylet. Dimensions of the stylet (Plate XIV: D) are as follows: convex side x = 43µm, concave side k = 50.5µm, length of distal opening e = 31.5µm, diameter of proximal opening a = 31µm, longitudinal axis (d) = 56µm. Bradynectes syltensis Faubel, 1974 (Plate XIV: F; Figs 78, 79; Tabs 5, 10) Synonymy. Bradynectes sterreri forma syltensis Faubel, 1974; p , fig. 6. Type locality. Beach off old Litoralstation, List, Sylt, North Sea, ANE; leg. Dez ; types : not available. Habitat. Eu- and sublittoral benthal, medium to coarse sand, down to 35cm sediment depth, marine. Geogr. distribution. ANW: North Sea (North Frisian Islands: Sylt Island, north of Ellenbogen, Koenigshaven) (Faubel 1977a Scherer 1985, Wehrenberg & Reise 1985) Morphological notes (Plate XIV: F). Body length up to 1.2mm by 0.15mm width, anteriorly truncated, posteriorly bluntly pointed. Caudal body-end with characteristically arranged caudal glands. Rhammite glands caudal of pharyngeal glands; rhammite tracks run lateral of pharynx simplex and brain forwards and gush out along frontal margin. In t.l. colourless the exception being the intestine contrasting yellowish. Eyes and rhabdites absent. Reproductive system with single testis and ovary on the right or left side. Ovary dominantly located between testis and gut. Vas deferens extremely short marked by a sphincter. Seminal and prostatic vesicle joined by intervesicular duct. Glands of prostatic vesicle extra-vesicular. Stylet (Plate XIV: F) hooked, proximally funnel-shaped, and distally with subterminal opening on the convex side; distance of distal and proximal opening of the convex side (x) averaged 31µm, distance of the concave (k) side averaged 32µm. The longitudinal axis (d) of the stylet accounts for 43µm. 159

160 Ecological notes. Bradynectes sterreri was regularly found in sandy, detritus rich sediments of semi-exposed beaches with numbers of up to 2 ind./10cm² (2.5-20cm sediment depth) (Faubel 1974, 1976 and unpubl. data) (Fig. 78, Tab. 5). More intense investigations to the distribution was given by Scherer (1985). B. syltensis was regularly found in the halos of the tubes of Arenicola marina (L.). A maximal number was reported by Scherer with 12 ind./10cm³ in July; own data presented in Fig. 79, are received in August 1992 (Faubel unpubl. data). After Scherer (1985), the species disappeared from the habitat from late summer to the end of winter. Small juveniles were observed only in February/March (Faubel unpubl. data). The species undergoes a univoltine life cycle with sexual reproduction phase from approximately May to August/September (Faubel unpub. data, Scherer 1985) (Tab. 10). Bradynectes sp. Tyler, 1976 (Fig. 56) Localities. South shore, 1.5 miles from inlet, New RiArrangement of gland necks and microvilliver, North Carolina, USA, ANW; types unknown. Habitat. Sublittoral fringe, benthal, medium to fine sand, marine. Morphological notes were only given to the ultrastructure of the adhesive organ (Fig. 56). Genus Dunwichia Faubel, Blome & Cannon, 1994 Diagnosis. Macrostomidae with male system of simplex type with cirrus. Discrete prostatic vesicle absent but with seminal prostatic vesicle. Ovary and testis single. Seminal bursa present, but atrium femininum and ovidut absent. Gonopores separate. Rhabdites and rhammites present. Type of the genus: Dunwichia arenosa Faubel, Blome & Cannon, 1994 Fig. 56. Bradynectes sp. A. ultrastructure of adhesive organ and associated rhabdite gland. B. Arrangement of gland necks and microvilli of a papilla, in transverse section. (after Tyler 1976) Dunwichia arenosa Faubel, Blome & Cannon, 1994 (Plate XVI: I-J; Fig. 11B) Type locality. Adam s Beach, Dunwich, North Stradbroke Island, Queensland, Australia, PCW, leg. March 1992; types: QM-B G (SS); Habitat. semi-exposed eulittoral beach and flat with fine to medium reddish brown sand (Md µm), OM % (beach) and % (flat), Sal (beach) and (flat); Geogr. distribution. PCW: Moreton Bay, Queensland, Australia, PCW. Paratypes : G (SS). Morphological notes (Plate XVI: I). Body length up to 1.0mm, head with more or less pointed horns laterally, each of which carrying 2-3 sensory spines; additionally, sensory hairs and spines of varying length around body. Rear body end spatulate with 24µm long ciliary tuft. Eyes absent. Colour whitish, in t.l. translucent with contrasting darker intestine. Crescentic brain anterior to mouth. Epidermis cellular, with intraepithelial nuclei, and invaginated dorsal rhabdite glands distributed in longitudinal rows over the dorsal body surface. Rear body end with glandular adhesive system. Excretory system absent. 160

161 Reproductive system with single testis and ovary. Testis on the left posterior to pharynx. Sperms spiralled, 48µm long. Ovary extends from posterior testis caudad. From ventral opening, close behind last oocyte, synctial seminal bursa arises dorsad. Bursal duct constricted distally by large secretory cells. Male copulatory organ of simplex type, consisting of seminal prostatic vesicle into which distally an unarmed cirrus is invaginated. Prostatic material is produced by extra-vesicular glands. Whole complex invested by a muscular housing. Distal short antrum masculinum present. Diagrammatic reconstruction of male and female copulatory system see Plate XVI: J. Genus. Haplomacrostomum gen. n. Diagnosis. Macrostomidae with single ovary and bilateral testes present. Male copulatory apparatus with seminal and prostatic vesicle, the latter incased into proximal portion of sclerotised stylet. Mouth and pharynx simplex posterior to brain. Separate gonopores. Type of the genus. Macrostomum contortum Beklemishev, 1951 Remarks. The establishment of the genus Haplomacrostomum is only based on the development of a single ovary. Key to the species of Haplomacrostomum. 1 rhammite tracks absent 2 - rhammite tracks present, stylet of Macrostomum hystricinum type with distal hook-like bend Haplomacrostomum contortum 2 stylet elongate tube-like with distal hook-like bend Haplomacrostomum australiensis - stylet unknown, eyes distinctly behind brain, with adhesive plate bearing sutle ciliary tuft Haplomacrostomum sp. Haplomacrostomum contortum (Beklemishev, 1951) comb. n. (Plate XIII: S-T) Synonymy. Macrostomum contortum Beklemishev, 1951; p , figs 20, Type locality. Krasnovodsk, Caspian Sea, EPA; leg Aug. 1914; types: deposition not recorded. Habitat. Algal aufwuchs on piles of cement, polyhaline. Geogr. distribution. EUROPE: RU-S: Caspian Sea: Bight of Astrabad, Lenkoran) (Beklemishev 1951, 1953). Morphological notes. Body length up to 1.5mm, translucent with intestine taking on yellowish colouration when diatoms ingested. Eyes black, with lens. Rhammite tracks present; rhabdites in bundles with up to 7 rods. Reproductive system with bilateral testes and single ovary. False seminal vesicle absent. Seminal and prostatic vesicle connected by intervesicular duct. Extravesicular prostatic glands enter in common with intervesicular duct prostatic vesicle (Plate XIII: T). Stylet (Plate XIII: S) with two spiral bends; the planes of the bends turned at an angle of about 90 from the main axis; stylet proximally funnel-shaped and distad tapering to a pointed tip. Ovary with thin walled, distally splitting into bilateral thick-walled oviducts. Oviducts filled with oocytes, inundated with alien sperm. Female atrium surrounded by great masses of cement glands. Haplomacrostomum australiensis (Faubel, Blome & Cannon, 1994) comb. n. (Plate XIII: U-V) 161

162 Synonymy. Macrostomum australiensis Faubel, Blome & Cannon, 1994; p , fig. 8. Type locality. Woolgoolga Creek, Coffs Harbour, New South Wales, Australia, PCW, leg. April 1992; holotype not deposited. Habitat. Eulittoral of sheltered brackish water estuary; very fine to fine sand (Md µm), of high contents of detritus (OM %), covered with green Cyanophyta and brown algae, Sal 16-26, brackish. Morphological notes (Plate XIII: V). Body length up to 1.0 mm, rear body end truncate with strong adhesive glands for attaching to substrate (Plate XIII: V). In t.l. colour yellowish with darker parts representing the gut. Eyes located behind crescentic brain. Rhabdites of smaller size distributed in serial rows over dorsal body surface. Sensory hairs and spines of varying length and stiffness present, principally at the body extremities. Subtle pharyngeal glands lie lateral to the pharynx. Excretory system absent. Reproductive system with bilateral testes lying postero-lateral to the pharynx and single ovary in the last third of body. Stylet 45.4µm long (extremities), d = 42.7µm. The stylet (Plate XIII: U) is tube-like, slightly curved funnel with a widened proximal base and a distal hooklike bend turned at an angle of about 90 from the main axis (Plate XIII: U). Female genital system with female atrium. Gonopores separate. The species is protandrous. Haplomacrostomum sp. (Faubel, Blome & Cannon, 1994) comb. n. (Plate XIII: Q-R) Synonymy. Macrostomum sp. Faubel, Blome & Cannon, 1994; p. 1002, fig. 9. Type locality. Adam s Beach, One Mile Beach, North Stradbroke Island, Moreton Bay, Queensland, Australia, PCW; types: G (SS). Habitat. Eulittoral, benthal with sandy sediments, marine. Morphological notes (Plate XIII: Q). Body length up to 0.78µm long, macrostomid-like in shape, i.e. greatest width in middle of body which is gradually reduced at the spatulate tail; spatulate tail disk-like with many adhesive glands (Plate XIII: Q). The rear end bears a subtle ciliary tuft. Anterior tip of body with bundles of 8-9 rhabdoids of parenchymal rhammite glands. Subepidermal rhabdite glands develop 1-2 rhabdite rods. Crescentic brain with characteristic median constriction. Eyes present. Epidermis provided with intraepithelial nuclei, supplied with sensory hairs and spines. Pharynx with extrapharyngeal glands; intestine densely ciliated with 15-25µm long cilia, is lined with palisade-like epithelial cells, ventrally twice as high as dorsal cells. The gut is filled with diatoms and unidentifiable microorganisms. Exretory system not determined. Reproductive system with bilateral testes and single ovary. Female system (Plate XIII: R) with ciliated vagina and proximal female atrium; vagina surrounded by massive cement glands. Male system not developed. The species is protandrous. Myomacrostomum Rieger, 1986 Diagnosis. Macrostomidae with muscle ring on gut. Rhammites penetrating brain. Asexual reproduction by paratomy. Adhesive organ of dolichomacrostomid type and sensory caudal organ present. Male copulatory organ with seminal vesicle, prostatic vesicle, and anteriadpointing stylet. Testis single just in front of male apparatus, slightly displaced to the left. Ovary single, medial, immediately in front of the testis. Type of the genus: Myomacrostomum unichaeta Rieger,

163 Remarks. According to Rieger (1986), the position of the genus Myomacrostomum within the Macrostomida is uncertain, however, the genus is distinctly not a member of the Dolichomacrostomidae. The single ovary, the close position of the testis to the male organ, and the asexual reproduction (paratomy) are persistent characters which are found within the Microstomidae. Only, the paired and unpaired arrangement of the caudal sensory organ point to relationships to the Dolichomacrostomidae (Rieger & Tyler 1974, Rieger 1986). However, the anatomy of the male copulatory apparatus, the separation of seminal and prostatic vesicle, and the absence of a preoral gut and ciliated pits prove a closer relationship to members of the Macrostomidae (cf. Rieger 1986). Notwithstanding the muscle ring on gut, the character of the Karlingiinae Rieger, 1971 and the new family Myozonidae, I prefer to establish the genus Myomacrostomum within the Macrostomidae because the stylet of Myomacrostomum seems to be more related to the outline of stylets of the species of the Macrostomum hystricinum group - distal prostatic vesicle encased by proximal funnel - than to the species of the genus Microstomum. Myomacrostomum unichaeta Rieger, 1986 (Plate XVI: K-L) Type locality. Close to mouth of New River Inlet at New River estuary, N.C., USA, leg. 1972; types: AMNH 1233 (holotype), 1234 (paratype). Habitat., marine. Morphological notes (Plate XVI: K). Body length up to 1.0 mm of male mature specimens; 2 zooids; posterior zooid with male reproductive organs (Plate XVI: K). Colourless, with slightly yellowish brown intestine and spotted due to rhabdite bundles. Rhammite glands present, posteriad bifurcating. Rhammites 20-30µm long. Obviously without prepharyngeal gut. Intestine with muscle ring on gut. Single ciliary tuft of sensory caudal organ µm long, Reproductive system. Testis small, spherical, close to funnel shaped stylet in posterior body-half. Stylet 25µm long (Plate XVI: L). Prostatic and seminal vesicle present. Efferent ducts of prostatic vesicle encased by the proximal funnel of the stylet. Myomacrostomum bichaeta Rieger, 1986 (Plate XVI: M) Type locality. 1km from mouth of New River Inlet at New River estuary, N.C., USA, leg. 1972; AMNH 1235 (holotype), 1236 (paratype). Habitat. Eulittoral benthos, sandbank, marine. Morphological notes (Plate XVI: M). Body length up to 0.6 mm of sexually immature specimens; 2 zooids;. Colourles, with slightly yellowish brown intestine and spotted due to rhabdite bundles. Rhammite glands present posteriad bifurcating. Rhammites 4-11µm long. Obviously without prepharyngeal gut. Intestine with muscle ring on gut. Two ciliary tufts of sensory caudal organs µm long, Reproductive system unknown. Genus Nynaeshamnia gen. n. Diagnosis. Macrostomidae with single ovary and testis. Male copulatory organ with seminal vesicle, prostatic glands, and evertable cirrus enclosed. Cirrus unarmed. Female system neither with vagina nor with antrum femininum. Gonopores separate. Male genital apparatus of simplex-type. 163

164 Type of the genus: Psammomacrostomum turbanelloides Karling, 1974 Etymology. The generic name refers to the type locality Nynäshamn, Sweden. Nynaeshamnia turbanelloides (Karling, 1974) comb. n. (Plate XVI: E-F) Synonymy. Psammomacrostomum turbanelloides Karling, 1974; p. 86, figs Type locality. Nynäshamn, south of Stockholm, Sweden, western Gotland Sea, BAL; leg. 26. Oct. 1952; types: not prepared. not deposited. Habitat. Stygal, coastal groundwater in the water edge, coarse sand, oligohaline. Geogr. distribution. ANE: English Channel (France: estuary of the Seine near Honfleur) (Sopott-Ehlers & Ehlers 2001). Morphological notes (Plate XVI: E). Body length up to 1.2mm, resembling a gastrotrich of the Turbanella-type, almost cylindrical with circular furrow at level of pharynx; typically spatulate, macrostomid-like rear end with tail-like flagellum emerging dorso-caudally; head with paired lateral tufts of sensory bristles. Epidermis with rhabdites. Eyes absent. Reproductive system with single testis on the left and ovary on the right. Fields of spermatogonia and oogonia about at mid-body. Male copulatory apparatus (Plate XVI: F) composed of seminal vesicle tapering distally, glandular part (prostatic part), and an arched cirrus which extends into funnel-shaped antrum masculinum. Female gonopore unknown. The spermatozoa correspond to the basic architecture of macrostomid sperm cells. The cortical microtubules are also subdivided into two contralateral sets, however, each set consists of a double row of contralateral microtubules with a few microtubules per row set apart from the others. Furthermore, membranous lacunae, dense-cored microtubules and existence of tubuliform organelles are unknown for other macrostomid species and do not fit the basic architecture (Sopott-Ehlers & Ehlers 2001). The presence of two dense ledges are as well as known from species of the genus Bradynectes Rieger & Sterrer. The characters, the exception being the two dense ledges, were hypothesised by Sopott-Ehlers & Ehlers to be autoapomorphic. Remarks. Karling (1974b) placed Psammomacrostomum turbellanelloides within the genus Psammomacrostomum Ax because of the development of an unarmed cirrus extending into a funnel-shaped antrum masculinum. The genus Psammomacrostomum is characterised through bilateral ovaries and a cirrus internus representing a male copulatory system of duplex type. In both the important characters, P. turbanelloides deviate from the diagnosis of the genus Psammomacrostomum and from those genera present in the family Macrostomidae. Therefore, P. turbanelloides has to be tranferred to the newly established genus Nynaeshamnia gen. n. Genus Omalostomum Van Beneden, 1870 Diagnosis. Macrostomidae with single ovary. Male copulatory apparatus with sclerotised stylet. Mouth located anterior to brain and eyes if latter ones present. Type of the genus: Macrostomum claparedei Van Beneden, 1870 Remarks. In the description of the species Omalostomum claparedei and O. schultzei made by Van Beneden (1870a) and Claparède (1863), respectively, nothing was said on the presence or absence of a prostatic vesicle (cf. v. Graff 1882, 1913). According to the authors, the stylet should be connected immediately with the seminal vesicle (cf. Fig. x). In Fig

165 (plate IV) Claparède reflected exactly the arangement of the male organs, however, the identification of each of the organs was partly invalid (cf. Fig. x: terms given by Claparède in parenthesis). Ferguson stated (1954, p. 144) that the description is meagre and it is possible that each will receive a new position once they are adaquately described. Omalostomum claparedei (Van Beneden, 1870) Van Beneden, 1870 (Plate XV: K) Synonyms. Macrostomum claparedii Van Beneden, 1870a; p , 132. Type locality. Concarneau, France, English Channel, ANE; types: unknown. Habitat. Eulittoral, between Fucus sp. and Zostera sp., marine. Morphological notes (Plate XV: K). Body length up to 0.37mm, macrostomid-like with rounded anterior end and posterior adhesive plate, transparent in t.l. Rhabdites present. Long bristles all-around body, terminally longer. Eyes behind pharynx simplex (Plate XV: K). Intestine with long cilia. Reproductive system with single ovary. Testes not mentioned. Ovary in second body-third. Female gonopore at level of beginning of last body-third. Male copulatory organ with slightly hooked stylet, distally pointed, proximally funnel-shaped (Macrostomum hystricinum type). Stylet proximally joined with seminal vesicle. Presence of prostatic vesicle unclear. Omalostomum schultzei (Claparède, 1863) Van Beneden 1870 (Fig. 57; Plate XV: L-M). Synonymy: Macrostomum schultzii Claparède, 1863; p , plate IV: figs 1-2. Type locality. St. Vaast de-la-hougue, France, English Channel, ANE; types: unknown. Habitat. Eu- and sublittoral phytal and benthal, between species of Fucus sp. and Zostera sp., brackish, marine. Geogr. distribution. ANW: USA (Virginia: Norfolk Peninsula, shallows of estuaries) (Ferguson & Jones 1949). Fig. 57. Omalostomum schultzei, male organ after Claparède Invalid terms given by Claparède in parenthesis. Morphological notes (Plate XV: L). Body length up to 0.37mm, macrostomid-like, not flattened, with blunt anterior end; posterior end with spatulate adhesive plate, its posterior tip bluntly shaped, transparent in t.l. Rhabdite bundles present. Eyes behind pharynx simplex. Reproductive system with single ovary. Testes not mentioned in the text but in Fig. 1 (Claparède 1863: plate IV) the testes obviously correctly reproduced. Ovary in second body-third. Female gonopore at level of beginning of last body-third. Male copulatory organ with stylet (Fig. 57), hooked, distally pointed, proximally funnel-shaped (Macrostomum hystricinum type). Stylet proximally joined with prostatic vesicle. Presence of prostatic vesicle not identified by Claparède. Remarks. Ferguson (1954, plate I: fig. 2) interpreted the figure given by Claparède (1863) and v. Graff (1913), that the stylet is proximally joined with a small prostatic vesicle and the latter connected with the seminal vesicle via an intervesicular duct (Fig. 57). 165

166 Species incertae sedis Omalostomum groenlandicum (Steinböck, 1935) Faubel, Blome & Cannon 1994 (Plate XV: N) Synonym: Protomacrostomum groenlandicum Steinböck, 1935; p , figs 1-2. Type locality. Charcot Harbour, Milne Island, Greenland, ANW; leg. 26. Aug. 1933; types: unknown. Habitat. Eulittoral benthal, detritus and clay, marine. Morphological notes (Plate XV: N). Body terminally rounded. Eyes present. Mouth opens terminally at anterior body-end. Pharynx simplex horizontally oriented. Pharyngial tube and gut ciliated. Brain dorsal at level of middle part of pharynx. Reproductive system with bilateral testes and ovaries. Male copulatory apparatus complicated with long, spirally convoluted stylet. In some, male apparatus agrees with Paramacrostomum tricladoides Riedel (after Steinböck 1935, p. 236). Genus Promacrostomum An Der Lan, 1939 Diagnosis. Macrostomidae with bilateral testes and ovaries. Female genital system with vagina, female pore, bursal duct and bursal pore. Male genital system with seminal and prostatic vesicle and penis stylet. Gonopores separate. Male pore posterior to female gonopore. Type of the genus: Promacrostomum paradoxum An der Lan, 1939 Remarks. Papi (1951b) and Sluys (1986) discussed the functional distinctions and terms of the different pores of the female genital system in the genus Promacrostomum. Papi described the pore of the female duct entered by cement glands, under the name porus ovipositorius and the pore which communicates with the female atrium and the exterior, under the name porus femininus. The inwards following duct of the latter was called vagina. Sluys (1986) brought forward the argument that the same names of structures should be used, which are considered to be homologous. Following, Sluys termed the pore of the duct entered by cement glands female genital pore and the inwards following duct vagina. The pore between the exterior and the female atrium, being not equipped with cement glands, was called bursal pore and the inwards following duct bursal duct. As outlined by Sluys, I agree with his postulation of a posteriorly located female gonopore and vagina in P. paradoxum, and an anteriorly located female gonopore and vagina in P. gieysztoria and P. palum. The respective ducts of the species of the genus Promacrostomum are homologous and, therefore, the terminology must be aligned. Key to the species of Promacrostomum: 1 female gonopore anterior to bursal pore 2 - female gonopore posterior to bursal pore Promacrostomum paradoxum 2 male stylet proximally funnel-shaped and with distal bend Promacrostomum palum - male stylet without proximal funnel, distally spoon-like Promacrostomum gieysztori Promacrostomum paradoxum An der Lan, 1939 (Plate XV: A-B) Synonymy. Promacrostomum paradoxicum: Ferguson 1954 (lapsus linguae). Type locality. St. Stephan, Lake Ohrid, Macedonia; leg. July 1937; types: deposition unknown. 166

167 Habitat. Sublittoral benthal, coarse sand to gravel, down to 1.0m water depth, freshwater. Morphological notes. Body length up to 1.0mm, typically macrostomid-shaped with rounded anterior end and spatulate posterior end surrounded with adhesive papillae. Sensory bristles short and strong. Intestine with tall, ciliated cells; Minotian cells not present. Reproductive system (Plate XV: A-B) with bilateral testes and ovaries. Vasa deferentia join evidently to a common vas deferens extending into the seminal vesicle. Seminal and prostatic vesicle connected via short intervesicular duct. Prostatic vesicle distally not encased into funnel-shaped proximal end of stylet. Distal tip of stylet with thickened sclerotised walls as being developed in Macrostomum tuba von Graff. Male stylet 40µm (d) long (Plate XV: B). Female system with ciliated vagina and female atrium. Proximally, female atrium connected rostrad via genito-intestinal duct with intestine and ventrad via a bursal duct with the exterior. The cranial part of female atrium and genito-intestinal duct walled with strong circular muscle fibres. Oviducts not observed. Male gonopore posterior to female gonopore. Remarks. An Der Lan (1939) did not present any data on the presence or absence of cement glands which would characterise either of the ducts as being a vagina. In accordance with the anatomy of the species of the genus Macrostomum, An Der Lan addressed the duct being posterior to the female atrium as vagina. Promacrostomum gieysztori (Ferguson, 1939) Papi 1951 (Plate XV: C-E; Tab. 1) Synonymy. Macrostomum gracile (non Pereyaslawzewa, 1893) Gieysztor 1931; p , pl. 13: fig. 5. Macrostomum gieysztori Ferguson, 1939; p , fig. 7. Axia gieysztori Ferguson 1954; p. 147, plate VII, figs Type locality. Rice fields of Albufera, Valencia, Spain, Europe; types: unknown. Habitat. Benthal, rice fields, basins on sand, thermophilic, freshwater. Geogr. distribution. EUROPE: Italy (Pisa), Spain (Girona) (Gamo & Norena-Janssen 1998, Papi 1951b, 1952). Morphological notes (Plate XV: C). Body length up to 2.0mm, terminally rounded, posterior spatulate, colourless. Sensory bristles 30µm long, irregularly spaced along margin; extremities with a mixture of long and short fine sensory hairs; adhesive glands at rear bodyend. Eyes present. Rhabdites, mostly in bundles, 8-13µm long. Rhammite tracks lacking. Protonephridia not observed. Reproductive system with bilateral testes and ovaries. Length of curved stylet 135µm (d), proximal opening 21.5µm (a) (after Papi 1951a, b, single squashed specimen somewhat deformed: d = 165µm, a = 37µm), its characteristic tip spoon-like (after Ferguson 1939: there are two flanges in the curved termination, the one on the convexity of the curve being longer than the other on the concavity of the curve, Plate XV: D)). Intervesicular duct absent; false seminal vesicles present. Female genital system with female gonopore, ciliated vagina, nonciliated female atrium, and bursal duct and pore to the exterior; communication between common oviduct and female atrium via cellular closure apparatus ( Verschlußapparat ). Female gonopore anterior to bursal pore. Haploid set of chromosomes: n = 3 (2n = 6). Spermatozoa thread-shaped, about 45µ long (m.l.s.), bearing two stiff bristles between 1 st and 2 nd third of spermatozoa (Bedini & Papi 1970). Promacrostomum palum Sluys, 1986 (Plate XV: F-J) Type locality. Elizabeth Springs, South Australia, S, E, leg. W. Ponder, E. Hershler, D. Winn, Sept. 1983; types: SAM-A, V ; AM-S, W , -2. Habitat. Freshwater. 167

168 Morphological notes based on preserved specimens (Plate XV: F). Body length up to 3.5mm by 0.75mm width, fore-end broadly rounded, posterior end spade-like, the lateral margins of which give rise to a dorsally directed ridge at either side of the body; the posterior margin displays a convex middle section. Bundles of rhabdites and rhammite-tracks present. Adhesive glands absent; a cyanophilous, granular secretion is discharged at posterior tip of body; gland cells situated in the parenchyma. Body-wall muscles conventional. Reproductive system with bilateral testes and ovaries; ovaries behind testes ventrally. Each of the oviducts runs directly towards mid-line of ventral body uniting to a common oviduct; the latter opens into the female atrium; cellular closure apparatus ( Verschlußapparat ) absent. Female atrium and bursal duct non-ciliated, vagina ciliated. Female gonopore posterior to bursal pore. Male copulatory organ with stylet, proximally funnel-shaped, encasing the prostatic vesicle. Distal stylet with pronounced bend towards ventral body surface. Seminal and prostatic vesicle joined by intervesicular duct. Diagrammatic reconstruction of male and female copulatory system see Plate XV: G-J. Genus Psammomacrostomum Ax, 1966 Diagnosis. Macrostomidae with bilateral testes and ovaries. Male copulatory organ of duplex type with seminal vesicle, prostatic glands, and evertable cirrus internus enclosed into cirrus bulb. Cirrus unarmed. Female system neither with vagina nor with antrum femininum. Gonopores separate. Female gonopore anterior to male pore. Type of the genus: Psammomacrostomum equicaudatum Ax, 1966 Psammomacrostomum equicaudatum Ax, 1966 [S 1723, p. 417] (Plate XVI: A-B, Fig. 9) Type locality. L Eyre estuary, Bassin d Arcachon, France, ANE; leg Ax, 1966; types: ZMU-G, P Habitat. Eulittoral, benthal, coarse sand, brackish, meso- and polyhaline. Geogr. distribution. EUROPE: Germany (Weser River Estuary: Bremerhaven, Sahlenburg) (Krumwiede & Witt 1995). Morphological notes (Plate XVI: A). Body length up to 1.2mm, greatest width behind midbody at level of ovaries, strongly dorso-ventrally flattened; frontal and caudal end bar-bellshaped. Along margin numerous bristles rising above body-cilia. Specimens lack eyes and are uncoloured. Posterior body form an adhesive plate bearing a ciliary bundle, 60-70µm in length. Rhabdites only developed dorsally. Epidermis with intra-epithelial nuclei; ventral cilia longer and densier than dorsal cilia. Body muscle wall developed as usual; dorso-ventral muscle fibres lateral and caudal. Pharynx duplex-type entered by pharyngeal glands. Proximally, strong retractors present. Gut short and extends backwards to level of oocytes. Minotian cells only in anterior part of intestine. Reproductive system with bilateral testes and ovaries. Testes in mid-body, ovaries in second body-half. In squash preparation vasa deferentia unite just before entrance into seminal vesicle. According to the analysis of two sagittal serial section series, the vasa deferentia seem to unite to a common vas deferens anterior to terminal oocytes. Male copulatory organ (Plate XVI: B) enclosed into cirrus bulb, consists of seminal vesicle, cirrus internus capped with prostatic vesicles, and distal antrum masculinum. Cirrus invaginated into cavity distal of seminal vesicle, representing a construction of duplex-type of copulatory organs (Karling 1956, p. 190). Sclerotised elements lacking. Total length of cirrus bulb 140µm (m.l.s.), about 100µm (m.f.s.) in sagittal section; cirrus 35-40µm in length (m.f.s.). Female system lacks vagina and female atrium. Female gonopore surrounded by extremely 168

169 large cement glands. Diagrammatic reconstruction of male and female copulatory system see Plate XVI: B. Psammomacrostomum bokarinensis n. sp. (Figs 58-59) Type locality. Palm Beach, Bokarina, Queensland, Australia, PCW; leg. Faubel, 24. Sept. 1997; 11. May 1998; types: ZIM-H, V Habitat. Eulittoral stygal, 15m exposed sandy beach slope with moderately sorted coarse sands, preponderance of larger grain size fractions than Md prevailing (+SkI), marine. Sediment parameter (type locality). 15m (40-45cm depth, cgt 50cm, hwl 34m): Md μm = φ 0.18, QDI 0.86, SkI +0.37, POM 0.58%, Sal 35. Geogr. distribution. PCW: Tasman Sea (New South Wales: Bulli; Kioloa), Coral Sea (Queensland: Magnetic Island, Alma Bay; Caloundra, Shelly Beach) Australia. Description (m.l.s.). Body length up to 0.6mm by 0.08mm width, typically macrostomidshaped with truncated fore-end and tail-like blunt posterior end (Fig. 58A); greatest width at level of genital organs; in t.l. body yellowish with intestine taking on colour of ingested food. Anterior margin provided mit bristles, 12µm long; fronto-lateral edges furnished with bundle of cilia, 32µm in length. Distance from anterior margin to frontal border of pharynx 157µm. Rhabdites and rhabdite bundles containing 2 to 6 rods, are intensively distributed over body- Fig. 58. Psammomacrostomum bokariensis sp. n. A. Dorsal view of slightly squashed specimen. B. Genital organs of slightly squashed specimen amplified. surface. Rhammite glands located postero-laterally of pharynx; rhammite tracks open along the anterior margin. Next to the anteriorly oriented rhammite tracks, rhammites are also sparsely distributed over the whole body. Length of rhammite rods varies from 6.64 to 21.1µm. Rim of blunt tail provided with 16 adhesive glands arranged very closely to each 169

170 other in a crest-like manner; maximum length of adhesive glands 3.8µm; the same length holds for the rhabdites. Additionally, adhesive glands being rhabdite-shaped, space along lateral margin. Posterior rim of tail, additionally, with tactile bristles, 18µm long, and a long ciliary filament ( Schwanzfaden of German authors), 51µm in length. Food diatoms. Reproductive system (Figs 58B, 59A) with bilateral testes and ovaries. Testes lateroposterior to mid-body and just anterior to ovaries. Vasa deferentia forming false seminal vesicle, join immediately the male copulatory bulb of duplex type. Copulatory bulb (Fig. 58B) thickly musculary walled, consists of proximal seminal vesicle and distal cirrus; proximal part Fig. 59. Psammomacrostomum bokariensis sp. n. A. Dorsal view of male genital apparatus. B. Dorsal view of posterior body of slightly squashed specimen. of cirrus prostatic like. Male gonopore 114µm distant from posterior end of body. Female system with musculary walled, ciliary atrium. Oviduct not observed. Genital pores separate. Remarks. The genus Psammomacrostomum Ax is characterised through bilateral ovaries and a male copulatory system of duplex type. Based on both of these characters, Psammomacrostomum bokarinensis clearly belongs to the genus Psammomacrostomum. Unaware the detailed anatomy of the male and female copulatory system, the most conspicuous characters of P. bokarinensis are heavy rhabdites serially lined dorsally and ventrally, interspersed with rhammites, posterior rim of tail with long adhesive papillae, and testes just anterior to the ovaries located in the posterior body-half. These features distinguish P. bokarinensis from P. equicaudatum. Psammomacrostomum sp. Tyler, 1976 (Fig. 60) Localities. South shore, 1.5 miles from inlet, New River, North Carolina, USA, ANW; types unknown. Habitat. Sublittoral fringe, benthal, medium to fine sand, marine. Morphological notes were only given to the ultrastructure of the adhesive organ (Fig. 60). Genus Siccomacrostomum Schmidt & Sopott-Ehlers, 1976 Diagnosis. Macrostomidae with single ovary and bilateral testes. Male copulatory organ of duplex type with cirrus invaginated into muscular, bulbous prostatic vesicle. Seminal vesicle and common gonopore present. 170

171 Fig. 60. Psammomacrostomum sp. Adhesive organ. A. Gland necks and microvilli in transverse section. B. Lateral adhesive organ with associated sensory cell. C. Distribution of anchor cell bodies (anc),releasing gland bodies (rg), and viscid gland bodies (vig). (after Tyler 1976) Type of the genus: Siccomacrostomum triviale Schmidt & Sopott-Ehlers, 1976 Siccomacrostomum triviale Schmidt & Sopott-Ehlers, 1976 (Plate XVI: C-D) Type locality. Barrington, Galapagos Islands, PSE, leg. Schmidt, Febr March 1973; types: ZMU-G, P Habitat. Eulittoral, benthal, sand, stygobiont, marine. Geogr. distribution. PSE: Galapagos Islands (Santa Cruz: Santa Cruz north, Playa Borrero, Bahía Academy; Baltra; Bartholomé; Floreana: Punta Cormorant; Hood: Bahía Gardner; James: Bahía James; Jervis; Marchena; Tower: Bahía Darwin) (Schmidt & Sopott-Ehlers 1976). Morphological notes (Plate XVI: D). Body length up to 0.4mm, anterior end broadly rounded, caudal end with adhesive plate, broadest in mid-body (Plate XVI: D). Caudal adhesive plate with adhesive tubes (glands), each of which 4µm long. Animals in i.l. whitish, in t.l. grey. Tactile bristles all-around body; about 15µm long, at terminal ends about 20µm long. Anterior end (head) with bilateral tufts of long cilia. Bundles of rhabdites all-over surface of body; single rods 4-5µm in length. Rhammite tracks dilate fan-like anterior to brain. Conspicuous rhabdite tracks extend to pharynx simplex. Eyes absent. Reproductive system (Plate XVI: C) with single ovary and bilateral testes in second body half. From common gonopore ciliated common duct arises dorsad, splitting into dorsal female atrium via vagina interna and into caudad directed male atrium. Vagina interna and male atrium non-ciliated. Cement glands and oviduct not observed. Proximal male atrium entered by a muscular cirrus invaginated into muscular prostatic vesicle. Prostatic vesicle and seminal vesicle joined by a short intervesicular duct. Ecological notes. Siccomacrostomum triviale settled dominantly the moist sand stratum of the median beach slope ( Feuchtsandzone of German authors) at low tide. From a total of 1,335 individuals collected, 1,263 individuals (94.5%) were distributed between 40cm and 160cm above chart datum (mlwl) (Schmidt & Sopott-Ehlers 1976). Genus Unsia Bulnes, 2007 Diagnosis. Macrostomidae with bilateral ovaries and testes. Male copulatory apparatus with seminal vesicle and distal antrum masculinum; penis, cirrus, and prostatic vesicle absent; prostatic glands enter distally into the antrum masculinum. Female system with usual components. Gonopores separate. Posterior body-end without adhesive papillae. Eyes and rhabdites present. Type species: Unsia suaedae gen. nov. sp. nov. Unsia suaedae Bulnes, 2007 (Fig. 61) 171

172 Type locality. Playa Baterías, partido Coronel de Marina Leonardo Rosales, provincia de Buenos Aires, Argentina; leg. May 3 rd, 2004; types: 1 sagittally sectioned specimen, in private collection. Habitat. Eulittoral of sandy beach, down to 5cm sediment depth, marine. Morphological notes. Body length up to 0.42mm by 0.08mm width (Fig. 60A), fusiform, elongated, slender; anterior end truncated, posterior end conical; caudal adhesive plate absent. Numerous tactile cilia in anterior body. In transmitted light, body colourless translucent. Epidermis with irregularly scattered colourless rhabdites. Cephalic glands poorly developed. Eye spots triangular. Brain bilobated. Mouth opening in anterior third of body, followed by a typical pharynx simplex and straight intestine. Fig. 61. Unsia suaedae Bulnes. A. Dorsal view in squash preparation. B. Diagrammatic sagittal reconstruction. C. Sagittal reconstruction of the male and female copulatory apparatus. (after Bulnes 2007). Reproductive system (Fig. 60C) with bilateral testes, just caudal of mouth, and ovaries in the middle of posterior body-half. Chains of growing up oogonia converge medio-caudad, generating caudally only one single mature oocyte which is received by the oviduct (length of oviduct corresponds diameter of oocyte). The ample female atrium non-ciliated and walled with glandular lining, passes over into the short vagina; vagina surrounded by cement glands. The male copulatory apparatus consists of a seminal vesicle and a distal ciliated antrum 172

173 masculinum muscularly walled. Vasa deferentia enter separately the seminal vesicle. Seminal vesicle and antrum masculinum joined via a short duct; transition marked by a strong sphincter. Prostatic glands discharge into the distal part of the antrum masculinum and gonopore. Male and female gonopores separate. Ecological notes. Bulnes (2007) considered Unsia suaedae as a rare species in the estuary. In total, eight specimens were collected in both localities during the sampling period. The species was present from May to November. The animals were dominantly distributed in the sediments of the spring region and upper beach slope down to 5cm as a maximum. Genus Velamacrostomum gen.n. Diagnosis. Macrostomidae with bilateral testes and ovaries. Stylets provided with lamellalike appendages along the main tube. Prostatic vesicle with smooth interior lining; extravesicular glands absent. Type of the genus. Macrostomum velastylum Brusa, 2006 Etymology. The new generic name Velamacrostomum is a combination of the prefix vela (veil, Engl. and lamella, Latin) and the genus name Macrostomum. Remarks. The Macrostomidae are essentially characterised by their outline to the stylets. The general outline of the stylets of the genus Macrostomum is tube-shaped, elongate or curved, or funnel-shaped with distal bend but without any accessory stylets. In some species stylets are provided with lamellae. In 1994, Faubel et al. excluded Macrostomum miraculicis Schmidt & Sopott-Ehlers from the genus Macrostomum which is characterised by an accessory stylet, and established the new genus Bradburia Faubel, Blome & Cannon, 1994 based on the description of the new species Bradburia australiensis Faubel, Blome & Cannon, Brusa (2006) described a new representative, Macrostomum velastylum, which stands out through the development of a stylet with three well developed lamellae along the main tube. Other Macrostomum species which have developed lamellae or auriculae, are Macrostomum catarractae Gieysztor, M. glochistylum Ferguson, M. saifunicum Nasonov, and M. auriculatum Nasonov (Plate XVII). The existence of these appendages on the tubes of the stylets characterises the new genus Velamacrostomum gen. n. Determination key of the species of Velamacrostomum. 1 stylet with more than 1 lamellae 2 - stylet with 1 lamella along distal bend Velamacrostomum saifunicum 2 stylet with 2 distal lamellae 3 - stylet with 3 lamellae along C-shaped tube Velamacrostomum velastylum 3 stylet hystricinum-shaped Velamacrostomum catarractae - stylet, elongate tube, distally turned up with sharpened lamellae-like margins Velamacrostomum glochistylum Velamacrostomum velastylum (Brusa, 2006) comb. n. (Fig. 62, Plate XVII: E) Type locality. Pond near littoral of river Atalaya, ( S W), Rio de la Plata, Argentina; leg. F. Brusa, Aug. 2, 2001; types: MLP-BA, 5554 (holotype),

174 Habitat. Eulittoral benthal, clay and mud, on floating vegetation: Pistia stratiotes L., Limnobium spongia (Bosc.) ssp. laevigatum (Humb. & Bonpl. ex Willd.), Salvinia biloba Raddi, Lemnaceae, from freshwater to oligohaline waters. Geogr. distribution. ASW: Rio de La Plata (Punta Piedras, La Matilde stream) (Brusa 2006). Morphological notes. Body length up to 1.68mm by 0.48mm width, anterior end broadly rounded, caudal end truncate with adhesive plate, broadest in mid-body. Anterior and posterior end with long rigid sensory cilia. Bundles of rhabdites, rods in groups of 2-3, abundant all-over surface of body, more abundant in posterior half; rhabdites scarcely distributed on ventral surface between mouth and female gonopore. Rhammite tracks not mentioned. Bilateral eyes behind brain at level of anterior pharynx simplex. Intestine extends to anterior region of male stylet. The species feeds on testate amoebae (Arcella sp.), rotifers, and diatoms. Reproductive system (Fig. 61C) with bilateral testes and ovaries and separate gonopores. Vasa deferentia enter separately musculary walled, piriform seminal vesicle. Seminal and prostatic vesicle connected via long muscular intervesicular duct. Prostatic vesicle with strong muscle wall and smooth interior glandular lining giving way central ejaculatory duct. Stylet (Fig. 61A, B) length d = 155µm, proximal width (a) about 36µm (calculated from Brusa 2006, Fig. 2A). Distal opening subterminal on the convexe surface close to the acuminate tip. Stylet C -shaped, with 2 lateral lamellae and 1 small lamella in mid-line of the distal convexe surface. Female system consisting of ciliated vagina and proximal female atrium which is provided with a sphincter at the transition into the common oviduct. Female atrium with ciliated interior lining, thick muscular wall, and externally surrounded by a great number of small, unicellular glands. Numerous cement glands surround the vagina totally. Fig. 62. Velamacrostomum velastylum. A. Scanning electron micrograph of the stylet. B. outline of stylet. C. Diagrammatic sagittal reconstruction. (modified after Brusa 2006). Ecological notes. The environmental data of the type locality were running at time of sampling (2. Aug. 2001) as follows: salinity 0, conductivity 879µS, total dissolved solids (TDS) 441mg/L, ph 6.28, O mg/L = 2.4% O 2 sat., T of water 11C. 174

175 Velamacrostomum catarractae (Gieysztor, 1938) comb. n. (Plate XVII: A-B) Synonyms. Macrostomum catarractae Gieysztor, 1938; p.216, fig Type locality. Waterfall in valley Strążyska, Siklava, Tatra Mountains, Europe; leg July 1934 ; types: deposition not recorded. Habitat. Sublittoral benthal, freshwater. Geogr. distribution. EUROPE: Poland (Krakòw: Ojcòw National Park; Tatra Mountains: Jaworzynka river) (Gieysztor 1939, Kolasa 1973). Morphological notes (re-description of Kolasa 1973) (Plate XVII: A). Body length up to 1.2mm, typically macrostomid outline; anterior end truncated, posterior end strongly waisted forming an adhesive disk which terminates posteriorly in a blunt point. Colour in t.l. brownish-yellow with intestine taking on colour of food content; colour whitish in i.l. Sensory cilia (up to 55µm long), single or in tufts of up to 16, irregularly spaced along body margin and extremities. Eyes small, brown or reddish-black in dorso-posterior position of brain. Bundles of rhabdites scattered over entire body surface, more abundant in tail region. Rhammite tracks present. Specimens feeds on rotifers. Reproductive system with bilateral testes and ovaries. Vasa deferentia join to common vas deferens formed as false seminal vesicle if sperm production is high. Seminal and prostatic vesicle connected by intervesicular duct. Extravesicular prostatic glands enter in common with intervesicular duct prostatic vesicle. Stylet (Plate XVII: B) funnel-shaped, with complicated distal part; stylet measurements: d = 60-70µm, a = 30-55µm. Sperm cells about 33µm long. Female genital system developed as usual, resembling Macrostomum boreale Riedel, Velamacrostomum glochistylum (Ferguson, 1939) comb. n. (Plate XVII: *C-D; Tab. 1) Synonymy. Macrostomum glochostylum Ferguson, 1939; p. 198, figs (lapsus linguae). Macrostomum glocostylum Hayes, 1938; p. (lapsus linguae). Macrostomum glochistylum Ferguson, 1939; p , figs Type locality. Milam Gap, Skyline Drive, Greene County, Virginia, USA, NEA; types: USNM-W, Habitat. Krenal, phytal, cold spring-fed swamps, altitude of 3,500 feet, freshwater. Morphological notes. Body length up to 0.8mm by 0.2mm width, typically macrostomidlike with slightly extended tail region, posteriorly truncated, anteriorly broadly rounded, colourless, with intestine taking on colour of food content. Rhabdites in packets of 2 and 3 or in larger packets of 6 to 9. Spines, up to 10µm long, at extremities and ciliary tufts spacing along lateral margins. Eyes located caudal of brain, not embedded in tissue of brain. Protonephridia with bilateral stems, excretory pore of which not located. Chromosome number n=3. Reproductive system with bilateral testes and ovaries. Vasa deferentia unite to form a common vas deferens which distends to a false seminal vesicle. Prostatic vesicle with extravesicular prostatic glands. Stylet (Plate XVII: D) 64µm long, curved funnel with widened proximal crenate base slightly tapering to an unorthodox termination: opening terminal and limited by a turned up and sharpened margin. Female system composed as usual. Gonopores separate. 175

176 Velamacrostomum saifunicum (Nasonov, 1929) comb. n. (Plate XVII: F-G) Synonymy. Macrostomum saifunicum Nasonov, 1929; p , Fig. 1. Type locality. Close to the Center of Ecological Research, Lake Biwa, Japan, EPA; leg. Nasonov, July 13, 1929, types: deposition unknown. Habitat. Phytal region, freshwater. Geogr. distribution. EPA: Siberia (South Ussuri area: Ussuri river, Saifun river, lake Vambabosa close to Ussuriysk), Japan (Chondo island near Tsuruga, Lake Kireto, Fukui Pref) (Nasonov 1929). Morphological notes (Plate XVII: G). Length of body up to 2.0mm (up to 2.5mm after Okugawa 1930), oval body with bluntly pointed anterior end and spatulate body-end occupied by numerous adhesive papillae. Colourless white in i.l., with intestine taking on brownish to yellowish colouration when food ingested. Rhabdites congregated in groups of 3 and 4 over the body surface. Eyes small, reniform; lying antero-dorsal to pharynx. Pharynx short, surrounded with numerous pharyngeal glands. Reproductive system with bilateral testes and ovaries. Obviously false seminal vesicle present. (Nasonov wrote: seminal vesicle sometimes constricted into two parts). Prostatic vesicle encased into proximal stylet. Intervesicular duct short, indistinct. Stylet cone-shaped with terminal rectangular bend. There is a fine lamella at the distal bend, which helically proceeds from the distal tip proximad and ends posterior of the bend; distally the stylet is obliquely truncated (Plate XVII: F). Length of stylet 130µm. Remarks. The descriptions of Nasonov (1929: M. saifunicum) and Okugawa (1930: M. kawamurai) differ in an essential point in the description of the outline of the stylet. Okugawa did not mentioned the presence of a lamella and wrote the stylet does not lie in a plane. That agrees with observations made by Timoshkin who collected M. kawamurai in lake Biwa-ko in 1996 (pers. com. Timoshkin). Family Myozonidae fam. n. Diagnosis. Macrostomida with muscle ring on gut and communicatio genito-intestinalis. Single testis on the left and ovary on the right or vice versa. Female system with seminal bursa and vagina. Male copulatory apparatus with cirrus or penial stylet. Gonopores separate; male pore caudal of female one. Peripheral parenchyma often with characteristic glandular cell layer responsible for colour of body. Pharynx simplex ventral, postcerebral. Type of the family. Myozona Marcus, 1949 Remarks. Within the family Macrostomidae the genus Myozona stands out on the basis of the muscle ring on gut and the communicatio genito-intestinalis. Myomacrostomum Rieger provided with a muscle ring on gut as well, lacks the communicatio genito-intestinalis. Based on the asexual reproduction (paratomy) as a persistent character, the species of the genus Myomacrostomum prove greater tendencies of relationship to the Microstomidae than to the Myozonidae where asexual reproduction processes are totally absent. In line with Sopott- Ehlers and Schmidt (1974b) who evaluate the muscle ring on gut as synapomophous character within the Macrostomidae and on the basis of the existence of a communicatio genitointesinalis, the species of the genus Myozona are transferred to the new family Myozonidae. The genus Myozona contained species with an unarmed cirrus (Myozona evelinae, M. lutheri, M. psila, and M. purpurea), and species with sclerotised elements in the male tract (M. aerumnosa and M. stylifera). In Myozona stylifera, the ejaculatory duct bears distally a stylet and M. aerumnosa is equipped with one to two hooks within the cirrus bulb. Based on 176

177 the different outline of the ejaculatory duct, M. aerumnosa and M. stylifera are distinctly different and diverge greatly from the other species of the genus Myozona. The derivation of hooks (M. aerumnosa) from a penial stylet (M. stylifera) must be excluded (cf. Sopott-Ehlers and Schmidt 1974b, p ), therefore, both the species have to be transferred to two different new genera, Myomarcozona gen.n. and Frisiazona gen.n., respectively. Myomarcozona aerumnosa is characterised by the autapomorphy of the cirrus bulb provided with inner hooks and Frisiazona stylifera by the autapomorphous character of a distal stylet. Investigations on Australian beaches revealed two species which belong clearly to the family Myozonidae through the presence of a muscle ring on gut and a communicatio genitointestinalis. However, both species lacks a true penis and a prostatic vesicle. The distal part of the ejaculatory duct works as cirrus and opens directly to the exterior. In this respect the species deviate from all species of the family and warrant the establishment of the new genus Australomacrostomum gen. n. Key to the genera of Myozonidae. 1 male copulatory apparatus with cirrus or penial stylet and prostatic vesicle 2 - male copulatory apparatus without penis and prostatic vesicle Australomyozona sp.n. 2 male copulatory apparatus with cirrus 3 - male copulatory apparatus armed with stylet Frisiazona gen.n. 3 cirrus unarmed Myozona Marcus - cirrus bulb provided with inner one or two hooks Myomarcozona gen.n. Genus Myozona Marcus, 1949 Diagnosis. Myozonidae with unarmed cirrus, prostatic vesicle and seminal vesicle. Prostatic vesicle could be modifiied or reduced to specific compartments of the ejaculatory duct. Type of the genus: Myozona evelinae Marcus, 1949 Key to the species of Myozona. 1 male organ without discrete prostatic vesicle 2 - male organ with discrete prostatic vesicle Myozona evelinae 2 discrete seminal vesicle absent 3 - discrete seminal vesicle present Myozona purpurea 3 female system with oviduct and sphincter Myozona lutheri - female system without oviduct and sphincter Myozona psila Myozona evelinae Marcus, 1949 (Plate XVIII: A-B) Type locality. Island of São Sebastião, Bay of Santos, Brazil, ASW, leg. Sept ; types: deposition not recorded. Habitat. Eulittoral, benthal, sandy beach, marine. Geogr. distribution. ASW: Argentina (Bahía Blanca estuary: Playa Baterías, Playa Arroyo Pareja) (Bulnes 2007). Morphological notes (Plate XVIII: A). Body length up to 1.2mm by maximum width of 0.3mm, anterior body end rounded with numerous long bristles, posterior end of body bluntly pointed; colour maroon caused by large parenchymatic cells arranged peripherically in the dorsal and ventral body parenchyma; precerebral cyanophilous glands lying ventrally, open to 177

178 the exterior at anterior margin. Epidermis with intra-epithelial nuclei and subdermal rhabdites. Eyes absent. Intestine with muscle ring anterior to mid-gut. Worms feed on diatoms. Reproductive system with single testis on the left and single ovary on the right side. Testis and ovary behind muscle ring on gut. Growing oogonia and spermatogonia abut on nourishing intestine behind muscle ring on gut. Male copulatory apparatus (Plate XVIII: B) with seminal and prostatic vesicle and distal cirrus resting in folded male atrium. The ventral epidermis provided with large adenal glands around male and female gonopore, obviously serving as prostatic or cement glands. Female system with ciliated vagina and proximal seminal bursa which is connected to the gut via a communicatio genito-intestinalis. Gonopores separate. Ecological notes. After Bulnes (2007), Myozona evelinae dominantly settled the eulittoral region knick (0m site) of sandy beaches in the Bahía Blanca estuary. The highest individual number mounted up to 38 specimens per 125cm³ in May. The species develops protogynous and represents a univoltine lifecycle. Sexually mature individuals could be collected in May. Myozona lutheri Papi, 1953 (Plate XVIII: C-F) Type locality. Beaches between Viareggio and Tirrenia, Italy, Tyrrhenian Sea, MED; types: deposition not reported. Habitat. Mid-littoral stygal, sandy sediments, marine. Morphological notes (Plate XVIII: C). Body length up to 0.5mm by about 0.1mm width, dorso-ventrally flattened, anterior end truncated, posterior rounded. Adhesive glands in posterior body-half. In t.l. body intensive yellow. Epidermis, obviously syncytial, with adenal nuclei and bundles of rhabdite rods. Ciliation restricted to ventral sole. Body muscle wall structured as usual; dorso-ventral muscle fibres present. Two types of dermal glands present (cf. Marcus 1949, Faubel 1974). Peripheral parenchyma and parenchyma around intestine with cyanophilous glandular cell layer, type 1; ventral area of fore-body free of that cells. These cells are interpreted being responsible for the intensive yellow colour of the body. In addition, the peripheral gland layer interspersed with erythrophilous pear-shaped glands, type 2, which open to the exterior via small ducts. Rhammite tracks open along anterior margin; glands of which lateral of pharynx simplex. Pharynx behind brain entered by extra-pharyngeal glands. Intestine with muscle ring on gut. Worms feed on diatoms. Reproductive system with single testis on the left and ovary on the right. Testis and ovary behind muscle ring on gut. Male copulatory apparatus with proximal bulbous duct directed caudad and distal cirrus directed ventrad, covered with circular and longitudinal muscle layers. According to Papi (1953, p. 23) lining of ejaculatory duct not clearly discernable. Seminal vesicle absent. Function of proximal bulbous duct indistinct, however, granular material was observed by Papi in squashed specimens. Ovary connected with seminal bursa via short oviduct. Distal oviduct with sphincter. Seminal bursa connected with intestine by a broad communicatio genito-intestinalis. Vagina present. Transition of seminal bursa into vagina and female atrium not discernable because of incompletely developed female system. Cement glands surround both gonopores. Diagrammatic reconstruction of male and female copulatory system see Plate XVIII: C-F. Remarks. Papi (1953, p. 25) reported that in his material (sixteen serially sectioned species) the female systems were incompletely developed or histologically indistinct. The same holds evidently for the male system based on the indistinctness of the epithelial lining of the male ejaculatory duct. Nevertheless, it is to suggest that the proximal bulbous part of the male duct represents a prostatic vesicle. If that is not the case, then, the species has to be transferred to a new genus. The species exhibits obviously a slight protandrous development. 178

179 Ecological notes. Myozona lutheri populated moist sand strata of mid-littoral sandy beach slopes down to 5cm sediment depth (Papi 1953, p. 25). Individuals were found all the year round. Sexually mature specimens occurred only from June to October. Myozona psila Sopott-Ehlers & Schmidt, 1974 (Plate XVIII: G-H) Type locality. Bahía Borrero, Santa Cruz, Galapagos Islands, PSE; leg. P. Schmidt, Febr to March 1973; types: ZMU-G, P 511 (holotype) (paratype). Habitat. Sublittoral sandy habitat, marine. Geogr. distribution. PSE : Galapagos Islands (Santa Cruz : Bahía Academy ; James : Bahía James ; Tower : Bahía Darwin ; Floreana : Punta Cormorant ; Jervis ; Marchena) (Sopott- Ehlers & Schmidt 1974b). Morphological notes (Plate XVIII: G). Body length up to 0.6mm, anterior end rounded, posterior end pointed; both terminal ends with bristles. Red-brown pigment, in t.l., distributed over dorsal surface in tiny cells. Rhammite tracks present in fore-body and around pharynx. Epidermis with adenal rhabdite bundles and glands. Muscle ring on gut about in mid-body. Intestine with Minotian cells. Reproductive system (Plate XVIII: H) with singel testis on the left and ovary on the right. Testis and ovary behind muscle ring on gut. Vas deferens extends into oval, muscular copulatory organ. Male organ, diameter 25-30µm (m.f.s.), wrapped by outer circular and inner longitudinal muscle layer. Dilator muscles connect copulatory bulb with body wall muscles. Bulbous organ with septum close to the proximal entrance of vas deferens, subdividing interior lumen into small proximal chamber and larger distal chamber. Proximal chamber at times with sperm representing seminal vesicle; distal chamber filled with prostatic material produced by extravesicular prostatic glands. A discrete seminal vesicle and prostatic vesicle not developed. After Sopott-Ehlers & Schmidt distal small, short penis papilla present. Evidently, the distal bulbous organ works as cirrus. Female system with ciliated vagina extending proximally into seminal bursa. Vagina closed by distal and proximal sphincter. Seminal bursa distally surrounded by intestinal walls. An incessant communicatio genitointestinalis absent. Distally, vagina surrounded by cement glands. Diagrammatic reconstruction of male and female copulatory system see Plate XVIII: H. Ecological notes. Myozona psila settled dominantly the moist sand stratum of the median beach slope ( Feuchtsandzone of German authors). From a total of individuals collected, 875 individuals (83,7%) were distributed between +70cm and +140cm above chart datum (mlwl) (Sopott-Ehlers & Schmidt 1974b). Myozona purpurea Faubel, 1974 (Plate XVIII: I-K; Figs 11, 78, 81, 83, 91; Tabs 5, 10) Type locality. South of harbour of List, Sylt, North Frisian Islands, North Sea, ANE, leg. Sept. to Nov. 1972; types: ZMU-G, P 741 (holotype) 742 (paratype). Habitat. Eulittoral exposed and semi-exposed beach slopes, stygal, medium sand above coastal groundwater table (cgt), marine. Geogr. distribution. ANE: North Frisian Islands (Sylt: all sandy beaches around) (Faubel 1974, 1977). Morphological notes (Plate XVIII: I). Body length up to 1.4mm by 0.2mm width, dorsoventrally flattened, anterior end slightly obliquely truncated, caudal end rounded, in t.l. colour reddish. Body-end with bristles. Fore-body with glandular organ which opens at frontal margin. Epidermis looks syncytial with adenal nuclei. Rhabdites, rhammites, and eyes absent. Body muscle wall structured as usual. Dorso-ventral muscle fibres present. Peripheral 179

180 parenchyma with cell layer tinged black with haematoxilin eosine. These cells are interpreted being responsible for reddish colour of body. Dorso-laterally, the peripheral parenchyma provided with erythrophilous glands which open to the exterior via small ducts. Pharynx simplex distally with extrapharyngeal glands. Intestine with Minotian cells, provided with muscle ring on gut anterior to mid-body. Intestinal cilia decrease caudad so that in the hind part cilia appear only sporadically. Food: diatoms. Reproductive system with single testis on the left and ovary on the right in the second half of body. Male copulatory apparatus consist of seminal vesicle and cirrus directed frontad and ventrad. Discrete prostatic vesicle absent. Based on the epithelial lining, the cirrus represents three compartments and is walled with inner longitudinal and outer circular muscle layers in continuation with body muscle wall. The proximal compartment is non-ciliated and syncytial; the lining contains cyanophilous finely granulated material; nuclei absent. Distad, epithelial lining loses glandular nature and becomes cellular and complete ciliation. The middle compartment dilated club-shaped, turns ventrad. Two types of epithelial lining present. Dorsal lining with ciliated normal cells and ventral lining with high, eosinophilous, glandular cells being sparsely ciliated. The distal compartment is in continuation with epithelial lining of epidermis but lesser ciliated. Female copulatory system with seminal bursa, female atrium and distal vagina. Seminal bursa proximally encased by caudal intestinum. A temporary broad connection in terms of a communicatio genito-intestinalis is absent, but access is temporarily possible via a small pore closed by a basophilous stopper. Seminal bursa with non-ciliated epithelium and sclerotised transition, bottle neck like, to female atrium. Female atrium with nucleate epithelial lining, less closely ciliated than vagina. Transition between female atrium and vagina marked by strong sphincter. Cement glands present in distal female atrium and distal vagina. Gonopores separate. M. purpurea is protandrous. Diagrammatic reconstruction of male and female copulatory system see Plate XVIII: J-K. Myozona sp. Tyler, 1976 (Fig. 5E) Locality. Bahia Honda Key, Florida, USA, ASW; types: not presented. Habitat. Exposed sandy beach, marine. Geogr. distribution. ANW: USA (Bogue Bank: 500m from Bogue inlet) (Tyler 1976) Morphological notes were only given to the ultrastructure of the adhesive organ (Fig. 5E). Genus. Frisiazona gen. n. Diagnosis. Myozonidae with penial stylet, prostatic and seminal vesicle. Communicatio genito-intestinalis present Type of the genus. Myozona stylifera Ax, 1956 Etymology. Frisiazona (Latin, f.), combination of the locality North Frisian Islands and genus name Myozona to Frisiazona. Frisiazona stylifera (Ax, 1956) comb. n. (Plate XVI: N-O; Fig. 78; Tab. 5) Synonymy. Myozona stylifera Ax, 1956; p , figs 1-6. Type locality. Kniepsand, Amrum, North Frisian Islands, North Sea, ANE, leg. 29. July 1951; types: deposition not recorded. Habitat. Semi-exposed eulittoral sandflat with medium to fine sand, up to 5cm sediment depth, marine. 180

181 Geogr. distribution. ANE: North Sea (North Frisian Islands: Amrum: beach near Norddorf; Westerhever Sand; Sylt: List; Belgian west coast) (Ax 1956b, Faubel 1974, Schockaert et al. 1989). Morphological notes (Plate XVI: N). Body length up to 1.0mm, dorso-ventrally flattened, anterior end truncated, caudal end pointed, in t.l. colour yellowish brown. Hind-end with bristles. Fore-body with glandular organ which opens at frontal margin. Epidermis with intraepithelial nuclei and adenal rhabdite bundles; cilia allround, the exception being the rear body-end. Rhammite tracks in the anterior body present. Eyes absent. Two types of dermal glands present (cf. Marcus 1949, Papi 1953, Faubel 1974). Peripheral parenchyma with gland layer, type 1, tinged bluish black with haematoxilin eosine. These cells are interpreted being responsible for the yellowish colour of the body. In addition, the peripheral gland layer interspersed with erythrophilous pear-shaped glands, type 2, which open to the exterior via small ducts. Pharynx simplex ciliated more intensively than epidermis, distally with extrapharyngeal glands. Intestine with Minotian cells and dressed totally with cilia. Muscle ring on gut at level of beginning of second body-third. Reproductive system with single testis on the left and ovary on the right located behind muscle ring on gut. Male copulatory apparatus with seminal vesicle and prostatic vesicle joined by a short intervesicular duct, and distal stylet. Prostatic vesicle distally encased into proximal, funnel-shaped stylet (Plate XVI: O). Length of stylet 50µm (Ax 1956b), 63µm (Faubel 1974). Female copulatory system consists of seminal bursa and distal non-ciliated vagina. Seminal bursa with nucleate, synycial lining and muscle wall of circular and longitudinal muscle fibres. Ventro-laterally, the oviduct opens into the bursa; entrance of oviduct closed by a sphincter. Seminal bursa joined with caudal intestine via broad genitointestinal duct. Female gonopore surrounded with cement glands. Gonopores separate. Genus Myomarcozona gen. n. Diagnosis. Myozonidae with cirrus armed with hooks. A temporary communicatio genitointestinalis present. Testis and ovary single. Male gonopore posterior to female pore. Type of the genus. Myozona aerumnosa Sopott-Ehlers & Schmidt, 1974 Etymology. In honour of Ernesto Marcus, integration of his name into the previous genus name Myozona to Myomarcozona. Myomarcozona aerumnosa (Sopott-Ehlers & Schmidt, 1974) comb. n. (Plate XVI: P-R) Synonym. Myozona aerumnosa Sopott-Ehlers & Schmidt, 1974; p , figs 5-7. Type locality. Santa Cruz, Galapagos Islands, PSE; leg. Schmidt; types: ZMU-G, P 521 (holotype) (paratype). Habitat. Sublittoral benthal, sandy habitat, marine. Morphological notes (Plate XVI: P). Body length up to 1.4mm, terminal ends rounded, reddish brown to yellow in t.l. Rhammite track present; frontally splitting up fan-like. Adenal rhabdite bundles with 5-7 rods 12-15µm in length. Epidermis dressed with cilia, the exception being the rear body-end. Adenal glands, in vivo yellow, with nucleus present. Pharynx simplex ciliated, passes over into gut the cubic cells of which provided with long cilia. Muscle ring on gut at mid-body; in cross-section lumen triangular. Caudal of muscle ring, two longish spots in squash preparation; these spots represent cells of intestine containing darkly stained granula, obviously functioning as Minotian cells. Distal pharynx with nerve ring and surrounded with rhabdite glands. 181

182 Reproductive system (Plate XVI: Q-R) with single testis on the left and ovary on the right. Testis and ovary located just caudal of muscle ring on gut. Male copulatory organ consists of powerful cirrus-bulb and small proximal seminal vesicle. Seminal vesicle seems to be the expanded distal part of the vas deferens without special epithelium and muscle wall. Cirrus bulb, with cirrus internus, walled with thick coat of ring and longitudinal muscles. The interior of the bulb is filled with syncytial foamy tissue; caudally at the entrance of the seminal vesicle, there is a tissue free area. One or two hooks, 12-13µm in length, are disposed peripherally of the distal cirrus bulb. Prostatic vesicle absent. Prostatic glands arranged outside of the cirrus bulb, enter into the porximal part of the cirrus. Female system with vagina, seminal bursa, and oviduct walled with circular muscle fibres. An incessant communicatio genito-intestinalis absent. Seminal bursa in close contact with caudal intestinum. Seminal bursa distally surrounded by intestinal walls. A connection between seminal bursa and vagina could not be pointed out in serial sections. Vagina lined with high ciliated cells. Female gonopore anterior to male pore. Genus. Australomyozona gen. n. Diagnosis. Myozonidae with simple male copulatory apparatus without cirrus or penis. True compact prostatic vesicle absent. Seminal vesicle passes over directly into the male gonopore. Prostatic glands and communicatio genito-intestinalis present. Type of the genus. Australomyozona hearnsi sp. n. Etymology. Australomyozona (Latin and Greek, f.), combination of the locality Australia where the species was found, and the genus name Myozona to Australomyozona. Australomyozona hearnsi n. sp. (Figs 63, 64A, 65) Type locality. Hearns Lake, Woolgoolga, New South Wales, Australia, PCW; leg. Faubel,. May 02, Habitat. Eulittoral benthal and stygal, 5m to 40m of exposed sandy beach slope with moderately sorted fine sands, preponderance of grain size fractions dominantly prevailing finer than Md (-SkI), marine. Sediment parameters. 10m (cgt 25cm, hwl 48m) Md μm = φ +1.68, QDI 0.81, SkI 0.19, POM 0.67%, Sal of cgt Geogr. distribution. PCW: Tasman Sea (New South Wales: Shelly Beach, Port Macquarie), Coral Sea (Queensland: Palm Beach, Bokarina). Description (m.l.s.). Body length up to 0.95mm by 0.12mm width, terminally rounded, anterior end indistinctly head-shaped (Fig. 64A); rear body-end with long bristles and rim of adhesive glands. Bundles of rhabdites irregularly distributed over the whole body, the number of which assembled 6 to 14 rods. At the rear body-end single rhabdites or rhabdites bundles assembled two or three rods dominant; rhabdites of posterior body-end longer than the rhabdite bundles with more than 6 rods in the anterior half. In t.l., the body looks transparent colourless, however, in the periphery of the parenchyma adenal cells gleaming weakly reddish, are densely dispersed over the whole body; all these reddish cells are characterised by a black spot. These black spots observed at lower magnification, dissolve to colourless stoppers in the epidermis at higher magnification, which close the efferent ducts of the reddish glands to the exterior (cf. Myozona kioloaensis). Digestive system consists of pharynx simplex, oesophagus, intestine with muscle ring on gut (540µm distant from anterior margin), and proximal genito-intestinal duct passing over into the female duct. 182

183 Fig. 63. Australomyozona hearnsi sp. n. Photomicrographs of the posterior body half. A. Male and female copulatory apparatus. B. Male copulatory apparatus. Fig. 64. A. Australomyozona hearnsi sp. n. B. Australomyozona kioloaensis sp. n. A.-B. Dorsal view after squeezed specimens. Reproductive system (Figs 63A,B, 64A) with single testis on the left and single ovary on the right. The testis originated close behind to the muscle ring on gut, passes over into the vas defernce. The distal portion of the vas deference distends to a false seminal vesicle which is received by the seminal vesicle. Male copulatory apparatus very simple developed, consists of only a seminal vesicle which leads immediately into the male gonopore. Penis or cirrus 183

184 absent. A true, compact prostatic vesicle is lacking, however, prostatic glands emensely developed in the rear body and completely embedding the slightly muscularised seminal vesicle, discharge their mucous contents directly in the distal ejaculatory duct. During copulation the distal ejaculatory duct will be protruded into the vagina. Female gonopore anterior to male one. Female duct not just yet developed. The species develops proterandrously. Ecological notes. Australomyozona hearnsi settled exposed sandy beaches in the warmer climes of the eastern coast of Australia (Fig. 65). The species favours deeper sediment layers of the upper beaches. That is identical with the habitat of Myozona purpurea Faubel, 1974 living in semi-exposed beaches of the North Frisian Island Sylt (Faubel 1974, 1976). hwl Port Macquarie: Shelly Beach 6 6 ind. (tot.): 42 n n 5 n 4 7 lwl 11 - n cgt m 20m 10m 5m 2m 0m 2m 5m 10m lb sr ub Fig. 65. Abundance of Australomyozona hearnsi along a profile of an exposed sandy beach from the warm temperate clime of the eastern coast of Australia. Each subsample represents a sample size of 25cm 3 (5cm² surface, 5cm depth), Abbreviations: cgt - coastal groundwater table; hwl - high water line; ind. (tot.) - total individual abundance per profile; lb - lower beach; lwl - low water line; n - not taken; sr - spring region; ub - upper beach. Australomyozona kioloaensis n. sp. (Figs 64B, 66-67) Type locality. Kioloa, New South Wales, Australia, Tasman Sea, PCW; leg. Faubel, May 25 th, Habitat. Eulittoral benthal and stygal, 1m (sr) to 15m (ub) of exposed sandy beach slope with well sorted to moderately well sorted fine sands, preponderance of grain size fractions dominantly prevailing larger than Md (+SkI), marine. Sediment parameters. Range from 1m (sr) to 15m (ub, cgt 49cm, hwl 22m) Md μm = φ to +1.82, QDI 0.38 to 0.54, SkI to +0.22, POM 0.36% to 0.65%, Sal of cgt 35 to 32. Geogr. distribution. PCW: Tasman Sea (New South Wales: Bulli). Description (m.l.s.). Body length up to 0.64mm by 0.07mm width, terminally rounded, anterior end distinctly head-shaped (Figs 64B, ). Rear body-end with rim of adhesive glands. In t.l. transparent colourless, the exception being slightly red adenal cells scattered in the periphery of the parenchyma. Each of these reddish cells, obviously of glandular nature, open 184

185 Fig. 66. Australomyozona kioloaensis sp. n. Photomicrographs of the posterior body half. A. Male and female copulatory apparatus. B. Male copulatory apparatus. to the exterior via a short glandular duct which is closed by a stopper. These stoppers tinge blackish (in t.l.) at lower magnifications, at higher magnifications the black spots become more and more greyish (cf. Australomyozona hearnsi). Bundles of small rhabdites, more numerous along the margins of body; assemble four to six rods. Rear end without bristles, but anterior end with lot of very short tactile bristles. Distance from anterior end to frontal border Kioloa - - ind. (tot.): lwl cgt m 20m 15m 10m 5m 3m 1m 0m 1m 3m 5m 10m 15m lb sr ub hwl Fig. 67. Abundance of Australomyozona kioloaensis along a profile of an exposed sandy beach from the warm temperate clime of the eastern coast of Australia. Each subsample represents a sample size of 25cm 3 sediment (5cm² surface, 5cm depth) (abbreviations see Fig. 45). of pharynx 97µm. Mouth passes over into 6µm long, strongly ciliated oesophagus assembled with pharyngeal glands, and intestine of about 250µm in length. Muscle ring on gut 313µm distant from anterior margin. Rear end of gut joined with female duct via a communicatio genito-intestinalis. Reproductive system (Fig. 64B, 66B) with single testis on the left and single ovary on the right. The testis is located at level of muscle ring on gut in the second body-half and give way 185

186 to the vas deferens distally distended to a seminal vesicle. Prostatic vesicle absent. The ejaculatory duct opens to the exterior close to the rear body-end. The female system is connected by a communicatio genito-intestinalis with the posterior end of the gut. The female atrium is oval in shape and strongly walled with a muscular sheath. Ecological notes. Australomyozona kioloaensis settled exposed sandy beaches in the warm temperate clime of the eastern coast of Australia (Fig. 67). The species favours deeper sediment layers of sandy beaches. Greatest depth (Fig. 67) was recorded near the high water line in 45cm sediment depth. That is identical with the habitat of Myozona purpurea Faubel and Antromacrostomum armatum Faubel living in semi-exposed beaches of the North Frisian Island Sylt (Faubel 1974, 1976). Family Dolichomacrostomidae Rieger, 1971 Diagnosis. Macrostomida with tubular pharynx directed posteriad; frontal glands behind brain, the ducts of which passing through brain. Common gonopore continuous with genital atrium in which the female system opens from anterior and the male system obliquely from posterior; usually a glandular accessory organ enters separately or in common with the male organ into the atrium. Testis single, anterior to or at level of single or paired ovaries. Male organ with seminal vesicle, prostatic vesicle, and stylet; stylet directed anteriad. Female apparatus with atrial bursa and characteristic bursa pieces; mouth-piece always with 2 small disk-like thickenings. Marine and brackish water inhabitants. Type of the family: Dolichomacrostomum Luther, 1947 Key to the subfamilies of the Dolichomacrostomidae 1 with accesory glandular organ 2 - accessory glandular organ absent Bathymacrostominae 2 stylet of glandular accessory organ merging into penial stylet proximally Dolichomacrostominae - stylet of glandular accessory organ if present, not joined with penial stylet Karlingiinae Subfamily Dolichomacrostominae Rieger, 1971 Diagnosis. Dolichomacrostomidae with long penis stylet joined with prostatic vesicle via an extended prostato-penial duct; stylet with characteristic torsions (exception being Megamorion Rieger & Sterrer 1968). Accessory glandular organ with glandular stylet merging into the penis stylet proximally. Vagina interna, bursal organ and spermatic duct present. Type of the subfamily: Dolichomacrostomum Luther, 1947 Key to the genera of the subfamily Dolichomacrstominae. 1 gut rhabdocoelous 2 - gut tricladoid like Paramacrostomum 2 accessory gland present 3 - accessory gland absent Megamorion 3 accessory gland single 4 - with paired accessory glands Dolichomacrostomum 4 with bilateral ovaries 6 - with single ovary 5 186

187 5 well developed sclerotised apparatus of bursal organ Paromalostomum - sclerotised apparatus of bursal organ reduced Meiocheta 6 (3: with bilateral ovaries) with lamella-like protuberance at penial stylet Cylindromacrostomum - without lamella-like protuberance at penial stylet Austromacrostomum Genus Dolichomacrostomum Luther, 1947 Diagnosis. Dolichomacrostominae with single testis and ovary; the latter with semi-paired germ centre (Rieger 1971c). Paired accessory glands with long, tube-shaped glandular stylet. Bursal duct present. Middel piece of sclerotised bursal apparatus cub-shaped joined immediately with the spermatic duct. Sperm tubes long, at thinner end curved. Type of the genus: Dolichomacrostomum uniporum Luther, 1947 Dolichomacrostomum uniporum Luther, 1947 (Plate XIX: A-C) Type locality. Tvärminne, Gulf of Finland, types: deposition not recorded. Habitat. Sub- and eulittoral benthal and stygal; in fine sand, fine sand mixed with shells or mud or gyttja; down to 1.0m water depth, marine, brackish. Geogr. distribution. BAL: Sweden (Skåne, Åhus), Kieler Bucht (Schlei: Schleswig, Große Breite; Fleckeby), Gulf of Finland (Tvaerminne: Bönholmsviken, Brännskär; Hangö: Bay Lilla Märsan, Vikarskär); ANE: Skagerrak (Halland, Laxvik), Irish Sea (North Wales: Llanbadrog, Porth Trecastell, Rosneigr, Traeth Bychan, Black Rocks) (Ax 1951a, 2008, Boaden 1963, Jaeckel 1962, Karling in Luther 1960, Karling 1974b, Luther 1947, 1960, Papi 1950, Rieger 1971c). Morphological notes (Plate XIX: A). Body length up to 1.0mm, filiform, terminal ends varying, sometimes rounded, sometimes bluntly pointed; posterior body-end with caudal organ; frontal end club-shaped. Terminal body-end with sensory bristles. In i.l. colour whitish with intensively yellow contrasting intestine. Rhammite glands laterally at level of pharynx; rhammite tracks open anteriorly; rhammites about 5µm long. Paired eyes dorsal of brain. Epidermis with depressed nuclei only in the fore-end; the remaining epidermis with intraepithelial nuclei; rhabdites and glands absent. Adhesive glands increasing in number caudad, present along whole margin. Mouth immediately behind brain; pharynx simplex penetrated by many extra-pharyngeal glands, with pharyngeal ring of glands; intestine ciliated, with Minotian cells the whole length. Food diatoms and larvae of Crustacea. Protonephridia with two lateral longitudinal stems; nephro-pore unknown. Reproductive system with single testis on the left in mid-body and single ovary on the right caudal to the gut. Common genital atrium ventrally ciliated and dorsally non-ciliated. Paired accessory glandular organs present. The glandular ducts intesively ciliated, unite immediately at the proximal end of the glandular stylet. Glandular stylet arched, averages 90µm in length. Male copulatory complex (Plate XIX: C) with seminal and prostatic vesicle joined by an intervesicular duct, and penis stylet. Prostatic duct ciliated in whole length, ends up in proximal funnel-shaped end of stylet. Male duct connected with glandular duct through muscle fibres. Male stylet about 170µm long. Female copulatory apparatus (Plate XIX: B) with oviduct, non-ciliated vagina, bursal organ, bursal duct, and spermiducal duct. Bursal organ with sclerotised apparatus consisting of distal mouth-piece, mid-piece and proximal tube. 187

188 Dolichomacrostomum sp. Gray & Rieger, 1971 Type locality. Stoupe Beck, Robin Hoods Bay,Yorkshire, England, North Sea, ANE; types: deposition not recorded. Habitat. Eulittoral benthal of an exposed sandy beach, grain size: M z φ between 1.89 and 1.96 and σi (sorting) between 0.54 and 0.55 (grain size determination after Folk 1968), marine. Genus Austromacrostomum Rieger, 1971 Diagnosis. Dolichomacrostominae with single testis and bilateral ovaries. Paired (?) accessory glands with long, tube-shaped glandular stylet. Bursal duct present. Middel piece of sclerotised joined immediately with the spermatic duct. Sperm tubes present. Type of the genus: Dolichomacrostomum mortenseni Marcus, 1950 Austromacrostomum mortenseni (Marcus, 1950) Rieger 1971 (Plate XIX: V-W) Synonymy. Dolichomacrostomum mortenseni Marcus, 1950; p , figs Type locality. Island of São Sebastião, Bay of Santos, Brazil, ASW; leg. 11. Sept. 1902; types: deposition not published. Habitat. Sublittoral, benthal, coarse sand covered with algae, marine. Geogr. distribution. SOW (Falkland Islands: Falkland) (Westblad 1952). Morphological notes (Plate XIX: V). Body length of fixed specimens up to 1.2mm by maximum width of 0.2mm, terminal ends slightly pointed, at level of brain a constriction (circular furrow) separates head and main body. Colour of body yellowish. Cephalic glands absent. Rhammite tracks open frontal; adhesive glands at posterior margin. Epidermis with dermal rhabdites and intra-epithelial nuclei. Eyes present. Minotian cells in the anterior part of intestine. Intestine ciliated, surrounded with muscle wall. Food diatoms, crusteans and eggs. Reproductive system (Plate XIX: W) with single testis on the right side and bilateral ovaries. The ovocytes touch the wall of the intestine and probably receive their aliments directly from the gut (Marcus 1950, p. 106). Common genital atrium and pore to the exterior. Male apparatus consists of twisted, thin glandular stylet and penial stylet tapering distad; distal end sickle-shaped. Both stylets are connected proximally. Glandular stylet proximally twisted (two spirals), merge into straight middle part; the transition between both parts seems articulated; both parts are sclerotised and surounded by a muscular wall. The distal part of this sclerotised glandular stylet opens into a non-sclerotised glandular middle part, followed by a slightly sclerotised duct, a bursal-shaped extension which lastly opens with a nozzle-like annulated tubule into the internal orifice of the very long antrum near the oldest ovocyte. The glands that produce the mass of secretion are compact, not epithelial and canaliculated ; they correspond to the paired accessory glands of Dolichomacrostomum uniporum (cf. Westblad 1952, p. 11). Bursal organ being finely granulated, with 2-3 sclerotised pieces which are distally spiralled (Plate XIX: W: sbo). Diagrammatic reconstruction of male and female copulatory system see Plate XIX: W. Remarks. The description of the bursal organ given by Marcus (1950, p , 106) and Westblad (1952, p ) on Dolichomacrostomum mortenseni seems to be partly misinterpreted. I suppose that Marcus and Westblad as well obviously did not realise that the glandular stylet opens into the genital atrium and the non-sclerotised glandular middle part corresponds to the bursal duct which extends into the bursal tissue, is followed by the middlepiece being slightly sclerotised; the bursal-shaped extension and the nozzle-like annulated tubule corresponds to the spermatic duct. Re-investigation of the species is very necessary. 188

189 Nomen nudum. Austromacrostomum sp. Rieger, 1977 Type locality. Rovinj, Istria, Croatia, Adriatic Sea, MED; leg. March 1969; types unknown. Habitat. Sublittoral benthal, sandy sediments grown with seagrasses or Posidonia, down to 10m water depth, marine (same site as type locality of Myozonaria bistylifera Rieger). Morphological notes not presented. Genus Cylindromacrostomum Rieger, 1971 Diagnosis. Dolichomacrostominae with bilateral ovaries and single testis. Complicate penial stylet. Accessory glandular organ single, sack or tube-like, provided with glandular stylet. Bursal duct present. Sclerotised apparatus of bursal organ with mouth-piece, mid-piece, and sperm tubes. Common genital atrium, ciliated. Type of the genus: Paromalostomum mediterraneum Ax, 1955 Cylindromacrostomum mediterraneum (Ax, 1955) Rieger 1971 (Plate XIX: G-I) Synonymy. Paromalostomum mediterraneum Ax, 1955; p , figs 1-2. Type locality. Off Laboratoire Arago, Banyuls sur Mer, Gulf of Lion, MED, leg. Sept. 1954; types: deposition not recorded. Habitat. Sublittoral benthal, fine sand, marine. Geogr. distribution. ANE: Bay of Biscan (Bassin d Arcachon: Banc d`arguin); MED: Adriatic Sea (Gulf of Venice: Venice), Black Sea (Sile), Sea of Marmara (Florya, Pendik) (Ax 1959, 2008, Rieger 1971b). Morphological notes (Plate XIX: G). Body length up to 0.8mm, anterior tip of body knobshaped, posterior end rounded with adhesive papillae. Two reniform eyes present. Caudal of brain large rhammite glands; rhammite rods run in lateral tracks anteriad to open at anterior knob-shaped body-end. Epidermis closely charged with bundles of rhabdites. Reproductive system (Plate XIX: H-I) with single testis and bilateral ovaries. False seminal vesicle, seminal vesicle and prostatic vesicle present. The prostatic vesicle passes into the penial stylet via a short duct. The accessory glandular organ opens with a long, curved, pointed stylet; length 42µm. The penial stylet is provided with a lamella-shaped protuberance at the end of its distal third. Bursal organ with sclerotised apparatus. Common gonopore passes dorsad into genital atrium. Remarks. Length of accessory stylet of Black Sea form 172µm (Ax 1959). Length of stylets of Venice form 153.7µm (penis stylet) and 135.8µm (accessory stylet) and of Marseille form 175µm (penis stylet) and 158µm (accessory stylet) (Rieger 1977, p ). Cylindromacrostomum notandum (Ax, 1951) Rieger 1971 (Plate XIX: D-F; Tab. 5) Synonymy. Paromalostomum notandum Ax, 1951; p , figs Type locality. Island of Sylt, North Sea, ANE; types: deposition not recorded. Habitat. Eu- and sublittoral benthal, sandy sediments, marine. Geogr. distribution. EUROPE: Germany (North Frisian Islands: Lister Tief between islands of Sylt and Rømø) (Wehrenberg & Reise 1985). 189

190 Morphological notes (Plate XIX: D). Body length up to 2.5mm, anterior tip of body knobshaped, posterior end rounded; adhesive papillae along lateral margins and posterior bodyend. In t.l. colour grey contrasting with brown intestine. Two eyes present. Rhammite glands latero-caudal of pharynx; rhammite rods, 15-25µm long, run in rhammite tracks frontad to open at knob-shaped frontal margin. Cyanophilous glands are interspersed within rhammite glands, the outlets of which open to the exterior in common with the rhammite tracks at the anterior margin. Epidermis closely charged with bundles of rhabdites, 10-15µm in length; at rear body-end rhabdites up to 26µm long. Each bundle encloses up to 10 rods of rhabdites. Body muscle wall structured as usual. Intestine with Minotian cells. Reproductive system (Plate XIX: E-F) with single testis and bilateral ovaries. Male complex with seminal and prostatic vesicle and distal ejaculatory duct ending distally with the complicated penial stylet. Glandular stylet, curved and distally pointed, proximally joined with the accessory glandular organ. Glandular organ surrounded with spiral muscle wall. Penial stylet provided with lamella-shaped protuberance at the end of its distal third, just anterior to the mid-loop of the stylet; distal end with complete spiral turn. Common gonopore present, passing dorsad into genital atrium. Genital atrium distally entered by cement glands. Vagina ciliated, extends rostrad and passes in common with spermatic duct into the distal part of the oviduct. Bursal canal non-ciliated. Bursal organ with sclerotised apparatus. Remarks. Ax (1951b, p. 38) wrote the sclerotised apparatus of the bursal organ stains intensively red with eosine opposite to the penial and glandular sclerotised ( cuticular ) stylets which always remain unstained. Therefore, the organic material of the bursal apparatus is evidently not composed of the same material as that of the penial stylets. Genus Megamorion Rieger & Sterrer, 1968 Diagnosis. Dolichomacrostominae with bilateral ovaries and single testis dorsal and lateral of pharynx. Penial stylet with by-tube of unknwon function. Accessory glandular organ absent. Bursal organ with sclerotised apparatus. Common genital pore opens into genital atrium. Type of the genus: Megamorion brevicauda Rieger & Sterrer, 1968 Megamorion brevicauda Rieger & Sterrer, 1968 (Plate XIX: J-M) Type locality. Raunefjorden, off Sletta, Norway, ANE; leg. Oct. 1964; types: depostion not recorded. Habitat. Sublittoral benthal, muddy sediments, 120m water depth, marine. Morphological notes (Plate XIX: J). Body length up to 0.75mm by 0.1mm width, cylindrical with short tail at rear body-end; anterior end bluntly pointed, colourless. Eyes absent. Epidermis with intra-epithelial and adenal nuclei; rhabdites adenal in anterior and posterior body-end; in median body, from mid-pharynx caudad, all rhabdites intra-epithelial; largest length of bundles of rhabdites (12µm) and closest pack of rhabdites in bundles (up to 14 rhabdites) along lateral sides and region anterior to tail. Length of rhabdites 5-6 µm. Rhammite tracks pierce brain and open at anterior margin in common with granular secretion. Adhesive glands absent. Body muscle wall structured as usual with outer ring and inner longitudinal fibres. Mouth passes into pharynx simplex, in life 100µm long. Marginal region around mouth non-ciliated; above non-ciliated area pharyngeal glands enter pharynx. Reproductive system (Plate XIX: K-M) with single testis and bilateral ovaries. Testis dorsal of pharynx extend laterad to the right side of body, passing into the vas deferens and runs laterally caudad. From ventral common gonopore the non-ciliated genital atrium arises 190

191 dorsad, into which the ejaculatory duct enters from the left body-side, the ciliated vagina from in front, and the bursal canal from latero-caudal. Bursal organ capped on dorsal part of genital atrium. Proximad, vagina meet oviduct taking over last oocyte. Gonopore surrounded with glands filled with 1-2µm large granula. Male complex consists of seminal vesicle, prostatic vesicle, and penis stylet. Distally, the prostatic vesicle passes into a short duct which join the proximal opening of the stylet. The opening of the stylet is about 10µm in diameter. Stylet 120µm in length, connected with a by-tube. By-tube branches off 32µm in front of proximal end of stylet. Bursal organ with sclerotised apparatus. Genus Meiocheta Rieger, 1971 Diagnosis. Dolichomacrostominae with single testis and ovary. Common genital atrium, ciliated. Sclerotised apparatus of bursal organ strongly modified, with mouth-piece, midpiece, and sperm tube; sperm tube short not longer than sclerotised apparatus. Bursal canal absent. Penial stylet connected with glandular stylet; the latter reduced to a sclerotised rod. Single accessory gland strongly reduced, sac-shaped. Type of the genus: Paromalostomum spiralis Ax, 1952 Meiocheta spiralis (Ax, 1952) Rieger 1971 (Plate XIX: N-O, *P-Q) Synonymy. Paromalostomum spiralis Ax, 1952; p , fig. 4a-f. Type locality. Flügge Sand, off Fehmarn, Kieler Bucht, BAL; leg. April 1951; types: deposition not reported. Habitat. Sublittoral benthal, median to coarse sandy sediments down to 17m water depth, marine, brackish. Geogr. distribution. ANE: North Sea (Skagerrak: Hallö), Irish Sea (Northern Ireland: Portaferry) BAL: Marstal Bugt (Vejsnaes Flak) (Ax 1952, Rieger 1971c). Morphological notes. Body length up to 1.0mm; colour grey in t.l. Eyes absent. Rhammite glands latero-caudal of pharynx; rhammite tracks run laterally frontad and open at anterior margin of body; rhammites 8µm long. Adhesive papillae distributed over the total body; caudal organ at posterior body-end. Epidermis with adenal nuclei and rhabdites (8µm long). Body muscle wall structured as usual. Nerve ring of pharynx above pharyngeal gland ring. Intestine ciliated, with intra-epithelial nuclei, Minotian cells, basal membrane, and muscle wall. Reproductive system with single testis and ovary close to each other on the left body side. From the ventral common gonopore the ciliated genital atrium arises dorsad, into which the ejaculatory duct enters from left side of body and the ciliated vagina from in front. Bursal organ capped on dorsal part of genital atrium; bursal canal absent. Cement glands surround distal part of genital atrium somewhat above gonopore. Male copulatory complex consisting of seminal vesicle, prostatic vesicle, and penis stylet. Seminal and prostatic vesicle connected by a short intervesicular duct; both vesicles surrounded with basal membrane and muscle wall. The ejaculatory duct of the prostatic vesicle is ciliated and passes into the penial stylet via a short duct. Penial stylet, µm long (Kieler Bucht) and 310µm long (Portaferry), distally strongly spiralled (up to 8 turns); median part of penial tube provided with two thickenings and one noose-shaped turn. Proximally, penial stylet with sclerotised rod. This rod (length 44-47µm) was homologised by Ax (1952, p. 104) with the glandular stylet of other Dolichomacrostominae. Accessory gland reduced to a small vesicle (5-10µm in diameter (m.f.s.) after Rieger 1971c, p. 664) containing several nuclei. Bursal organ of the femaly system separated by a membrane from the surrounding parenchyma; its tissue 191

192 syncytially and interspersed with large vacuoles. Sclerotised apparatus of the bursal organ consisting of mouth-piece, mid-piece and spermtube as well, greatly modified compared with that of other Dolichomacrostomidae. Length of the sclerotised apparatus 36-40µm (Ax 1952, p. 104) and 20µm (Rieger 1971c, p. 668). Diagrammatic reconstruction of male and female copulatory system see Plate XIX: O, *P-Q. Genus Paramacrostomum Riedel, 1932 Diagnosis. Dolichomacrostominae with tricladoid like gut. Bilateral ovaries present. Glandular stylet long, tube-shaped; accessory gland evidently present. Sperm tubes long; spermatic duct large. Bursal duct unknown. Common genital atrium. Bundles of rhabdites adenal. Type of the genus: Paramacrostomum tricladoides Riedel, 1932 Paramacrostomum tricladoides Riedel, 1932 (Plate XIX: R-U) Type locality. Near Goothaab, Disko Bay, Davis Strait, ANW; types: deposition not recorded. Habitat. Sub- and eulittoral benthal, sandy and muddy substrates; down to 2.0 m water depth, marine, brackish. Geogr. distribution. ANW: David Strait (Greenland: Godhavn); ANE: North Sea (Korsfjord, Bergen) (Riedel 1932, Westblad 1954). Morphological notes (mainly after Rieger 1971c) (Plate XIX: R). Body length up to 2.4mm. Rhabdites limited to the dorsal surface, more numerous laterally; rhabdite bundles depressed beneath body muscle wall. Length of rhabdites up to 10µm. Rhammite glands dorso-lateral of pharynx; rhammite tracks open subterminally. Ventrally, adhesive papillae distributed along body margins. Pharynx simplex with nerve-ring. Longitudinal nerves embedded in body muscle wall and united to tail-ganglion at rear body end. Reproductive system with separate gonopores after Riedel (1932); with common gonopore after Rieger (1971c). The following characters given after Rieger (1971c). Wether the testes are developed singularly or plurally remains unknown. Bilateral ovaries extend ventrolaterally of the gut from behind the pharynx simplex caudad to the bursal organ. Paired oviducts open into the common genital atrium into which the penis and glandular stylet enter as well. Rostrally of the genital atrium cement glands are present, marking the position of the vagina developed as blind sack. Male complex (Plate XIX: S) with seminal and prostatic vesicle joined by an intervesicular duct. The ejaculatory duct dilates distally of the prostatic vesicle to an oval vesicle which is encased by the proximal part of the complicate penis stylet. Penis stylet with characteristic lamellar protuberance distal of the middle turn. Glandular stylet, 290µm long, connected with the accessory glandular organ. Form and position could not exactly be identified. Female apparatus (Plate XIX: T)with bursal organ containing the cuticular apparatus. Cuticular apparatus with five sperm tubes and sclerotised spermiducal duct. Presence of mid-piece indistinct. Sperm tubes µm long. One of the sperm tubes is positioned with its thinner end in the dilated part of the spermiducal duct. Distally, sperm tube with characteristic mouth-piece (Plate XIX: U). Presence of a bursal duct could not be answered. 192

193 Genus Paromalostomum Meixner in Ax, 1951 Diagnosis. Dolichomacrostominae with single testis and ovary. Accessory glandular organ single, sack or tube-like, provided with glandular stylet. Bursal duct present. Sclerotised apparatus of bursal organ with cup or funnel-like mid-piece provided with differently outlined lappets. Mid-piece joined with distal spermatic duct via mouth-piece. Mouth-piece with terminal thickenings. Sperm tubes present. Common genital atrium, ciliated. Type of the genus: Omalostomum dubium de Beauchamp, 1927 Key to species of the genus Paromalostomum. 1 with sperm tubes 3 - without sperm tubes 2 2 without spiral turns of distal end of penial stylet Paromalostomum scilliensis - with two spiral turns of distal end of penial stylet Paromalostomum subflavum 3 without complete turn of distal end of penial stylet 6 - with spiral turns of distal end of penial stylet 4 4 mid-loop of penial stylet with spiral turns 5 - mid-loop of penial stylet with indistinct turns Paromalostomum atratum 5 mid-loop of penial stylet with one spiral turn Paromalostomum minutum - mid-loop of penial stylet with two spiral turns Paromalostomum fusculum 6 (3: without complete turn of distal end of penial stylet) bursal canal non-ciliated 7 - bursal canal partly ciliated Paromalostomum massiliensis 7 without distal turn of glandular stylet 9 - with distal turn of glandular stylet 8 8 glandular stylet averaging 60 µm in length Paromalostomum parvum - glandular stylet averaging 95 µm in length Paromalostomum proceracauda 9 distal tip of glandular stylet funnel-shaped Paromalostomum dubium - distal tip of glandular stylet pointed Paromalostomum coronum Paromalostomum dubium (de Beauchamp, 1927) (Figs 68, 78-79; Plate XX: D-E; Tab. 5) Synonym: Omalostomum dubium de Beauchamp, 1927 ; p , fig. 3. Type locality. Bassin d Arcachon (Plage de Moulleau) France, ANE ; types: deposition not recorded. Habitat. Sublittoral, eulittoral, benthal; sand, mud; down to 0.5m water depth, marine, brackish. Geogr. distribution. ANE: Bay of Biscay (Bassin d Arcachon: La Teste, Petit Nice, Le Moulleau); North Sea (Belgium coast-line, Islands of Sylt, Amrum, Fanø, Danmark: Esbjerg); Skagerrak (Halland, Laxvik), Gullmarfjord (Klubban); Irish Sea (North Wales, Anglesey: Cemaes Bay); BAL: Kieler Bucht (Schlei, Surendorf, Schönberg, Bülk, Stoller Grund), Sweden (Skane, Ahus); MED: Gulf of Lion (Golfe d Aigues-Mortes), Black Sea (Sile) (Ax 1951a, 1959, 2008, de Beauchamp 1927, Boaden 1963, Faubel 1977a, Fize 1963, Hellwig 1987, Karling in Westblad 1953, Pawlak 1969, Remane 1955, Scherer 1985). Morphological notes (Fig. 68). Body length up to 2.0mm; adhesive glands small, insignificant; colour grey. Epidermis with basal membrane and bundles of rhabdites; intraepithelial nuclei present, the exception being parts of the anterior end. Posterior end with adhesive glands. Median rhammite track splits into two conical bundles distal at the frontal margin. Reproductive system (Plate XX: D-E) with single testis and ovary orientated on the left side ventromediad. Testis somewhat behind mid-body. Common gonopore about 120µm 193

194 Fig. 68. Paromalostomum dubium de Beauchamp, A. Total view from dorsal. B. sclero-tised organs of bursal organ. C. male stylets (after de Beauchamp 1927). distant from hind end. The common genital atrium receives penial and glandular stylets latero-caudally from left, vagina and bursal canal. Bursal organ with sclerotised organs consisting of mouth-piece, mid-piece and sperm tubes. Male complex with seminal vesicle, prostatic vesicle, male stylet, accessory gland with distal glandular stylet. Penial stylet averaging 190µm in length, without spiral anterior end, and glandular stylet averaging 105µm, with funnel-shaped distal end. Prostato-penial duct short. Development protandrous. Paromalostomum atratum Rieger, 1971 (Plate XX: L-M) Type locality. Near of Fiascherino, Bight of La Spezia, Ligurian Sea, MED; leg. Sept. 1967, types: deposition not recorded. Habitat. Sublittoral benthal, medium to coarse sand, sand mixed with shells, down to 3.0m water depth, marine. Geogr. distribution. MED: Ligurian Sea (Palmaria Island) (Rieger 1971c). Morphological notes. Body length up to to 1.5mm; hind end roundish, fore-end distinct knob-shaped; anterior and posterior end with sensory bristles; colour grey with darker contrasting gut in t.l., colourless with white gut in i.l. Rhabdite bundles depressed into body muscle wall, with up to 15 rods (rhabdite rod up to 11µm long). Anterior body with rhammite tracts arising from glands posterior to pharyngeal area, dorso-lateral of gut. Tracks unite at anterior end to two conical bundles. Eyes absent. Rear body end with duo-gland-adhesive-organs. Body muscle wall structured as usual. Pharynx simplex tubeshaped; just above mouth ducts of rhabdite glands of pharyngeal gland ring open into pharynx in a dense arrangement; the glandular bodies of which lie ventrally and laterally of the pharynx. Length of rhabdites varies between 2 and 4 µm. Glands with finely granulated secretion are present, additionally. Reproductive system with single testis on the left and ovary on the right. From ventral common gonopore the ciliated genital atrium arises dorsad, into which the ejaculatory duct enters from caudal or dorso-caudal, the ciliated vagina from medio-frontal, and the bursal canal of the bursal organ from latero-dorsal; bursal organ capped on dorsal part of genital atrium. Cement glands pour into the short vagina. Bursal canal non-ciliated. Bursal organ bordered by a distinct membrane; tissue of bursal organ with granules of different size. Sclerotised apparatus of bursal organ (Plate XX: M) consists of mouth-piece, 11-13µm long, with two disc-shaped thickenings, mid-piece, crescentic, 30 µm in length, and 1-2 sperm tubes, µm long, with sperm vesicles; additional sperm tubes not connected with midpiece, present in number of one to ten. Male complex composed of seminal vesicle connected via short intervesicular duct with prostatic vesicle and penial stylet. Prostato-penial duct ciliated from proximal end of stylet to proximal end of prostatic vesicle. Male stylet µm long; glandular stylet 50-60µm long. Duct of accessory gland ciliated. Development protandrous. Reconstruction of male and female copulatory system see Plate XX: L-M. 194

195 Paromalostomum coronum Spurr, 1983 (Plate XX: P-Q) Type locality. Griffith s Head Beach, Reid State Park, Georgetown, Maine, USA, ANW; types: AMNH-NY, 922 (holotype), (paratypes). NHR-S, Habitat. Eulittoral, benthal, sand, marine. Geogr. distribution. ANW: USA (Maine: Georgetown, Massachusetts: Manomet); Canada (N. Brunswig: St.Andrews). Morphological notes. Body length up to 3.5mm, extremities of body truncated, anterior body with rhammite tracts arising from glands at pharyngeal area. Adenal rhabdite bundles with up to 12 rods; adhesive papillae scattered over entire body; posterior end with adhesive duo gland cells and anchor cell; eyes lacking. Colour white, with intestine taking on colour of food content. Reproductive system. Ovary and testis somewhat posterior to mid-body; testis and ovary on left side. Male apparatus consisting of seminal vesicle, prostatic vesicle, accessory gland, penis stylet, and glandular stylet (Plate XX: P). Accessory gland without muscular wall. Penis stylet, averaging 178 µm in length, with two sections: distal rigid one 68µm long and proximal flexible, twisted one 110µm long. Glandular stylet 50µm long. At its base, penial stylet fused with the glandular stylet. Bursal canal non-ciliated. Sclerotised apparatus of bursal organ composed of three parts: mouth-piece, 35µm in length, mid-piece, and sperm tubes averaging 141µm; mouth-piece extend into spermatic duct. Unattached sperm-tubes are free in the bursa. In sexually mature specimens, up to two attached and/or unattached sperm tubes present; maximum length of sperm tubes 162µm. Sperm either in a small sac distally or in a large sac totally surrounding the sperm tube. Paromalostomum fusculum Ax, 1952 (Plate XX: A-C; Figs 13, 78-80,85-87; Tabs 3, 5,10) Type locality. List, Island of Sylt, North Sea, ANE; types: deposition not recorded. Habitat. Eu- and sublittoral benthal, sand, marine. Geogr. distribution. ANE: North Sea (Islands of Amrum, Sylt, Lister Tief between Sylt and Rømø, Westerhever Sand; England: Robin Hood s Bay, Stoupe Beck Sand, Filey Beach; Belgium coast-line, The Netherlands: Scheldt estuary), France: Ile de Callot, Roscoff; Skagerrak (Gullmarfjord: Kristineberg, beach of Klubban); MED: Golf of Lion (Marseille: Cap Canaille). (Ax 1952, Ehlers 1980, Faubel 1974, 1977a, Gray & Rieger 1971, Hellwig 1987, Pawlak 1969, Rieger 1971c, Wehrenberg & Reise 1985). Morphological notes (after Ax 1952, Pawlak 1969, Rieger 1971c). Body length up to 1.3mm, extremities of body truncated, anterior body slender, posteriad gradually increasing, broadest at last body-third (Plate XX: A); colour brownish due to ingested diatoms. Frontal and hind end provided with stiff bristles. Eyes absent. At level of brain two rhammite tracks run forwards to open in common with frontal glands along anterior margin. Epidermis with intra-epithelial and partly depressed nuclei; with adenal rhabdite bundles, up to 15 rods per bundle, averaging 7 rods; bundles up to 20 µm long. Body muscle wall structured as usual with outer circular and inner longitudinal fibres. Lateral nerve stems extending from brain backwards; nerve ring of pharynx above pharyngeal gland ring. Intestine with cells of Körnerkolben descreasing caudad. Gut filled with diatoms. Reproductive system with single testis and ovary on the left. From ventral common gonopore ciliated genital atrium arises dorsad, into which the ejaculatory duct enters from left, the short ciliated vagina from medio-rostral, and the short non-ciliated bursal canal from dorsal. Bursal organ capped on dorsal part of genital atrium. Cement glands pour ventrally into vagina and into distal genital atrium. Male apparatus (Plate XX: B) with seminal vesicle, 195

196 prostatic vesicle, penial stylet, accessory gland and glandular stylet. Penial stylet 165µm long; glandular stylet 70 µm long. Penial stylet and glandular stylet proximally fixed with each other. Seminal and prostatic vesicle joined by a short intervesicular duct. Prostato-penial duct ciliated from proximal end of prostatic vesicle to proximal basis of penial stylet. Bursal organ with sclerotised apparatus (Plate XX: C). Sclerotised apparatus consists of mouth-piece, 7-8µm long and with single disc-like thickening close behind funnel shaped distal end, midpiece and sperm tubes; sperm tubes µm long; in sexually mature specimens, up to 3 unattached sperm tubes present. The mouth-piece opens into a small vesicle which narrows rostrad, forming the small spermatic duct. Mid-piece joined to bursal canal by muscle fibres. Development protandrous. Ecological notes. P. fusculum settles semi-exposed flats and beaches which are relatively poor in detritus (Pawlak 1969, Hellwig 1987). The vertical distribution of the species is given in Fig. 80 for a semi-exposed sandy beach and flat. Maximal depths down to 60cm (10m beach slope, Fig. 80) were recorded by Pawlak (1969). The population dynamic of specimens distributed on semi-exposed beaches is given in Fig. 85. Maximal numbers of specimens were found in May and Sept./Oct. Hellwig (1987) reported high densities, averaged 13.5 ind./10cm² and 31.7 ind./10cm², in August from two sites of lentic sandy beaches of the Königshaven, Island of Sylt. The life cycle of P. fusculumum is given in Tab. 7. The sexual reproduction phase proceeds in spring. P. fusculum developes protandrously. More information P. fusculum see chapter Ecological Account (Figs 78-80, 85-87, Tabs 5, 7, 10). Paromalostomum massiliensis Rieger, 1971 (Plate XX: J-K) Type locality. Ile de Plane, Archipelago of Riou, Gulf of Lion, MED; leg. M. Brunet April and June 1968, types: deposition not reported. Habitat. Sublittoral benthal, free flats of sand mixed with shells down to 10m water depth near meadows of Posidonia spp., marine. Morphological notes. Body length up to 1.3mm; body ends roundish; colour grey. Rear body end with large tubular glands containing secretion of very thin, closely packed, pointed rods. Rhabdite bundles depressed into body muscle wall, with up to 15 rods. Anterior body with rhammite tracts arising from glands posterior to pharyngeal area. Rhammite rods 20µm long. Eyes absent. Body muscle wall structured as usual. Reproductive system with single testis and ovary on the right. From ventral common gonopore the ciliated genital atrium arises dorsad, into which the ejaculatory duct enters from caudal or dorso-caudal, the ciliated vagina from in front, and the bursal canal enters from latero-dorsal. Bursal organ capped on dorsal part of genital atrium. Cement glands pour into the short vagina. Proximal part of accessory gland, filled with secretion, about 150µm long (m.f.s.) and distal part of accessory gland, free of secretion, 50µm long (m.f.s.). Prostatic duct with cilia from distal part of prostatic vesicle to basis of proximal penial stylet. Sclerotised apparatus of bursal organ (Plate XX: K): mouth-piece 11-15µm long, mid-piece 36-37µm long, and attached sperm tube about 107µm long; unattached sperm tube may present. Bursal canal partly ciliated. Paromalostomum minutum Rieger, 1971 (Plate XX: H-I) Type locality. Lido at Alberoni, Gulf of Venice, Adriatic Sea, MED; leg. Sept. 1967, types: deposition not reported. Habitat. Sub- and mid-littoral benthal; fine sand poor in detritus, mud; down to 1.5m water depth, marine, brackish. 196

197 Morphological notes. Body length up to 0.6mm by mm width at level of genital opening; hind end roundish, fore-end distinct knob-shaped. In i.l. colour transparent with brown intestine; in t.l. brownish with dark brown contrasting gut. Anterior body with rhammite tracts arising from glands posterior to pharyngeal area. Adhesive glands present over entire body; rear body end with caudal organ. Rhabdite bundles with up to 15 rods. Eyes absent. Protonephridia present lateral of the region of the bursal organ on the right body-side. Predator on nematodes. Reproductive system (Plate XX: H-I) with single testis on the left and ovary on the right. From ventral common gonopore the ciliated genital atrium arises dorsad, into which the ejaculatory duct enters from caudal or dorso-caudal, the ciliated vagina from in front, and the non-ciliated bursal canal enters from latero-dorsal. Bursal organ capped on dorsal part of genital atrium. Cement glands pour into the short vagina. Male copulatory apparatus (Plate XX: H) with seminal and prostatic vesicle, penial stylet, accessory gland and glandular stylet. Length of penial stylet µm and glandular stylet 55-65µm. Duct of accessory gland totally ciliated. Bursal organ (Plate XX: I) with mouth-piece, 8µm long, mid-piece, and attached sperm tube, µm long. Unattached sperm tubes could be present Mouth-piece projects into proximal part of spermatic duct. Paromalostomum parvum Rieger, 1971 (Plate XX: R-S) Type locality. Lido at Alberoni, Gulf of Venice, Adriatic Sea, MED; leg. types: deposition not reported. Habitat. Sub- and mid-littoral benthal; fine sand poor in detritus; down to 1.5m water depth, brackish, marine. Morphological notes. Body length up to 0.6mm by mm width at level of genital opening; hind end roundish, fore-end distinct knob-shaped. In i.l. colour transparent with brown intestine; in t.l. brownish with dark brown contrasting gut. Anterior body with rhammite tracts arising from glands posterior to pharyngeal area. Adhesive glands present over entire body; rear body end with tubular glands (up to 50µm long) containing secretion of very thin, closely packed, pointed rods. Rhabdite bundles with up to 15 rods. Eyes absent. Reproductive system (Plate XX: R-S) with single testis on the left and ovary on the right. From ventral common gonopore the ciliated genital atrium arises dorsad, into which the ejaculatory duct enters from caudal or dorso-caudal, the ciliated vagina from in front, and the non-ciliated bursal canal from latero-dorsal. Bursal organ capped on dorsal part of genital atrium. Cement glands pour into the short vagina. Male apparatus with seminal vesicle, prostatic vesicle, penial stylet, tubular accessory gland (60-70µm long), and glandular stylet. Prostato-penial duct totally ciliated from proximal end of penial stylet to proximal end of prostatic vesicle. Penial stylet with varying length between µm. Glandular stylet with varying length between 55-65µm. Proximal part of acessory gland, filled with secretion, 60-70µm long (m.f.s.) and distal part of accessory gland, free of secretion, 35 µm long (m.f.s.). Bursal organ with mouth-piece, 8-12µm long, mid-piece, 18µm long, and attached sperm tube, µm long. Unattached sperm tubes absent. Mouth-piece, disc-shaped thickening close behind funnel-shaped distal end, extend into spermatic duct. Paromalostomum proceracauda Pawlak, 1969 (Plate XX: F-G; Figs 7, 78; Tab. 5) Type locality. List, Island of Sylt, North Sea, ANE; leg. types: deposition not recorded. Habitat. Eu- and sublittoral benthal, sandy sediments, marine. 197

198 Morphological notes. Body length up to 1.5mm, slender anterior body with blunt frontal end, greatest width of body at last body-third, posterior end roundish with long, stiff hairs; in. t.l. colour of body greyish. Eyes absent. From rhammite glands located laterally of brain, rhammite tracks run frontad to open at anterior margin. Adenal rhabdite bundles (length 9-12µm) developed in groups of 5, are distributed over the body. Epithelium of pharynx and gut ciliated; intestine with Minotian cells. Preferably, predator on nematodes. Reproductive system (Plate XX: F-G) with single testis and ovary on the right side; testis anterior to ovary in mid-body at right body-side. From ventral common gonopore the ciliated genital atrium arises dorsad, into which the ejaculatory duct enters from caudal or dorsocaudal, the ciliated vagina from in front, and the bursal canal from latero-dorsal. Bursal canal ( Bursastiel after Pawlak 1969) non-ciliated. Bursal organ capped on dorsal part of genital atrium. Cement glands pour ventrally into proximal part of vagina and into distal genital atrium. The vagina dilate anteriorly, just caudally of the last oocyte, into a small vesicle called female antrum. Penis stylet (Plate XX: F) about 165µm long. Accessory gland sac-shaped; distally, accessory glandular duct ciliated. Glandular stylet 95µm long, straight, gradually narrowing distad; distal end strongly curved. Length of mouth-piece 8µm, mid-piece about 45µm, and sperm tubes about 100µm; measurements of male and female sclerotised organs after Rieger (1971c, p. 651). Paromalostomum scilliensis Faubel & Warwick, 2005 (Plate XX: N-O) Type locality. St. Martin s flats, Moth s Ledge, Celtic Sea, ANE; leg. May 2002; types: BMNH-L , WM: (stored on CD-ROM). Habitat. Eu- and sublittoral benthal, sandy sediments, marine. Morphological notes. Length of body of living sexually mature specimen up to 2.9mm, when squashed under a cover glass. Body ends rounded but rear body end somewhat pointed. Colour greyish with darkly contrasting gut and ovary. Intestine taking on yellowish brown colouration when diatoms ingested. Eyes, rhabdites, adhesive glands and tactile cilia absent around margin of body. Rhammite tracks running from anterior tip of body to the level of pharynx bilaterally. The species feeds on small nematodes, nauplii of harpacticoids, diatoms and detritus particles. Reproductive system (Plate XX: N-O). Single testis and ovary on the left side of body. Testis anterior to ovary. Seminal vesicle small, joined via a short intervesicular duct with the oval prostatic vesicle (198µm long). Male stylet apparatus (Plate XX: N) consisting of penis stylet and glandular stylet. Penis stylet 172µm long, the twisted proximal part of which 85µm long and distal straight tube 87µm long; the glandular stylet is 182µm long. The glandular stylet is joined with a single accessory gland; the penis stylet joins the 198µm long prostatic vesicle. The bursal sclerotised organ (Fig. x) consists of mid-piece (42µm long) and mouthpiece (56µm long). The mid-piece looks like a clog; the mouth-piece bears distally a disc shaped terminal thickening (Plate XX: O). Sperm tubes absent. A pyriform vesicle containing sperm opens into the proximal part of the mouth-piece. Paromalostomum subflavum Sopott-Ehlers & Schmidt, 1974 (Plate XX: T-U) Type locality. Santa Cruz, Galapagos Islands, PSE; leg Schmidt, types: deposition not recorded. Habitat. Sub- and eulittoral benthal, sandy sediments, marine. Morphological notes. Body length up to 1.0mm, body ends bluntly rounded, with long tactile cilia, hind end with prominent adhesive glands. Epidermis taking on colour from 198

199 circular enclosures from yellow to red. Rhammite track branches in front of brain into four smaller tracks running to the anterior tip. Pharyngeal glands extend far caudad. Bilateral fields of large rhabdites just posterior of pharyngeal glands. Adenal bundles of rhabdites distributed over whole body irregularly. Reproductive system (Plate XX: T-U) with testis and ovary in second body half; testis on right and ovary on left side of body. Male copulatory apparatus (Plate XX: T) with seminal vesicle, prostatic vesicle, penial stylet ( µm long), accessory glandular organ, and glandular stylet (40-45µm long). A long prostatic duct joins the proximal part of the penial stylet. Penial stylet and glandular stylet proximally fixed with each other at proximal turn of penial stylet. Distal end of penial stylet forms a S-shaped spiral (two turns); middle loop of stylet with one turn. Distal tip of glandular stylet hooked. Accessory gland without muscle wall; glandular duct non-ciliated. Bursal organ with syncytial tissue, capped on common genital atrium. Bursal apparatus with mouth-piece extending into spermatic duct and doubleflapped mid-piece; flaps distally connected by an articulated joint being furrow-shaped. Mouth piece, 40µm long, with two disc-like thickenings. Bursal canal present. Nomina nuda. Paromalostomum sp. Tyler, 1976 (Fig. 5D) Localities. Beach near Iron Steamer Pier, Bogue Banks, North Carolina, USA, ANW;; types unknown. Habitat. Sublittoral fringe of exposed beach, benthal, medium sand, marine. Morphological notes were only given to the ultrastructure of the adhesive organ (Fig. 5D). Reproductive system (after Rieger 1977). Length of penis (p) and accessory (a) stylet from Bogue Banks (number of specimens = 22): mean (p) = (s.d. = 12.19), mean (a) = (s.d. = 6.89); length of penis (p) and accessory (a) stylet from New River Inlet (number of specimens = 5): mean (p) = (s.d. = 9.76), mean (a) = (s.d. = 3.08). Paromalostomum spp. Rieger, 1977 (Plate XX: V-X) Localities. North Carolina, USA, ANW; Florida, USA, Tunesia, MED; types unknown. Habitat. Marine. Morphological notes not presented. Subfamily Karlingiinae Rieger, 1971 Diagnosis. Macrostomidae with penial stylet connected immediately with prostatic vesicle. Stylet straight, distally often with complicated folds. Accessory glandular organ mostly present, distally surrounded by strong muscles; if accessory glandular stylet present then not merged with penial stylet. Bursal organ separated from genital atrium via long bursal duct. Sclerotised bursal apparatus with mouth-piece, mid-piece, and sperm tube. Spermatic duct lacking. Type of the subfamily: Karlingia Ferguson, 1954 Key to the genera of the Karlingiinae. 1 with mucle-ring on gut 3 - without muscle-ring on gut 2 2 without endoskeleton of body wall Karlingia Rieger 199

200 - with endoskeleton of body wall Acanthomacrostomum Papi & Swedmark 3 accessory glandular organ without stylet Paramyozonaria Rieger - accessory glandular organ with stylet Myozonaria Rieger Genus Karlingia Ferguson, 1954 Diagnosis. Karlingiinae with single testis and ovary. Stylet simple, not thickened; with accessory prostatoid glandular organ and stylet; mouth-piece with disk-like thickenings, midpiece cup-like and distal spermatic duct. Muscle-ring on gut absent. Spermatic duct developed as simple continuation of mouth piece. Type of the genus: Dolichomacrostomum lutheri Marcus, 1948 Remarks. The genus Karlingia was established by Ferguson 1954 and contained only the species Karlingia lutheri (Marcus). Investigations on sandy beaches of Australia revealed three species new to science, Karlingia arrawarrensis sp. n., Karlingia barbelae, sp. n., and Karlingia bulliensis sp. n., which solely on the basis of its configuration of the male and female copulatory organs clearly belong to the genus Karlingia. The new species distinguish distinctly from Karlingia lutheri through the development of a single sperm tube in the bursal organs. Further differences are given in the outline and size of the accessory glandular and male stylets. The characters for the establishment of the species M. arrawarrensis sp. n., M. barbelae sp. n., and M. bulliensis sp. n. are given essentially in the different outline and size of the sclerotised male and female organs. Other characters are the position of the ovaries (on the left side of body in M. barbelae, on the right in M. arrawarrensis and M. bulliensis), the absence of rhammite tracks (M. arrawarrensis, M. bulliensis) and the development of two different types of rhabdites (M. arrawarrensis). The genus Karlingia at present contains four species including the three described in this paper. Determination key to the species of genus Karlingia. 1 bursal organ with sperm tube 2 - bursal organ without sperm tube, mid-piece and mouth piece present Karlingia bulliensis 2 bursal organ with only one sperm tube 3 - bursal organ with more than one sperm tubes Karlingia lutheri 3 straight stylet tube with distal semi-circle bend, ovary on the left Karlingia barbelae stylet with distal semi-circle bend and kink in its midst, ovary on the right Karlingia arrawarrensis Karlingia lutheri (Marcus, 1948) Ferguson 1954 (Plate XXI: A-B) Synonymy. Dolichomacrostomum lutheri Marcus, 1948; p , pl. II: figs Type locality. Beach of Guarujá near Santos, Bay of Santos, Brazil, ASW, leg. July 1947; types: deposition not recorded. Habitat. Eulittoral, benthal, shelly sand, marine. Geogr. distribution. ASW: Argentina (Bahía Blanca estuary: Playa Baterías, Playa Arroyo Pareja) (Bulnes 2007). 200

201 Morphological notes (Plate XXI: A). Body length up to 1.8mm by a maximum width of 0.15mm; fore-end truncated with bristles and cephalic glands, rear body-end tapering to a short tail with adhesive papillae. Eyes and rhabdites absent. Adhesive glands space irregularly along body margin. Epidermis with intra-epithelial nuclei and subdermal glands. Body muscle wall with powerful longitudinal fibres. Mouth with immense pharyngeal glands extending caudad up to mid-body. Intestine with ingested diatoms. Minotian cells present. Reproductive system with single testis on the left and ovary on the right side. Common genital atrium present. Vas deferens distends to false seminal vesicle; seminal vesicle and prostatic vesicle surrounded with muscular wall. A short muscular constriction between the vesicles represent the intervesicular duct. Male stylet (Plate XXI: B), 33µm long, with spiralled distal end and without glandular tube. Accessory glandular organ, 30-35µm long, with sclerotised tube, about 15µm long, enters genital atrium at opposite side of vagina. Glandular stylet, in middle part bent, with two openings of same diameter. Bursal organ (Plate XXI: B), ovoid after Marcus (1948), with two sclerotised sperm tubes, up to 80µm long, midpiece cup-shaped, about 10µm long, and disk-like thickenings of mouth-piece (cf. Rieger 1971b, p. 302); mouth piece µm in length. Ecological Notes. After Bulnes (2007), Karlingia lutheri commonly settled the sandy beaches investigated in the Bahía Blanca estuary. The abundance of species varied between one and seven specimens per 125cm³ sediment. Sexually mature individuals were collected in autumn and spring whereas in the latter season the individual numbers were highest. Karlingia arrawarrensis sp. n. (Fig. 69) Type locality: Arrawarra Headland, Ocean View Beach, (30 o 04 S, 151 o 06 E), New South Wales, Australia, PSW; leg. Faubel, Aug Habitat. Eulittoral benthal and stygal, 5m to 10m of exposed sandy beach slope with moderately well sorted and well sorted fine sands, preponderance of finer grain size fractions than Md prevailing (-SkI), marine. Sediment parameters. 5m (0-10cm depth, GWL 10cm): Md μm = φ 2.3, QDI 0.59, SkI 0.27, POM 1.36; 10m (0-20cm depth, GWL 20cm): Md μm = φ 2.39, QDI 0.44, SkI 0.25, POM 0.88%, Sal 35. Geogr. distribution. PSW: Australia (New South Wales: Bulli, Kioloa). Description (m. l. s.). Body up to 1.1mm in length by 0.2mm width, slightly oval in shape, with characteristic blunt macrostomid fore-end and somewhat bluntly pointed posterior end (Fig. 69A). Greatest width of body anterior to mid-body. Posterior end with long rigid tactile cilia and adhesive papillae on its rim. Along blunt fore-end ducts of cephalic glands open to the exterior. In t.l. basic colour yellowish, with intestine taking on yellow to orange due to ingested food. Eyes, typical rhammite tracks, and glands absent. Two types of rhabdites present: oval rhabdites single or in bundles with 2 to 4 rods (7.9µm long) arranged rather evenly in distinct rows and adenal rhabdites (17.03µm long). Pharynx simplex tube-shaped, massive; just above mouth ducts of glands of pharyngeal gland ring open into pharynx in a dense arrangement; the glandular bodies of which lie ventrally and laterally of the pharynx. The ducts of the cephalic and pharyngeal glands charateristically thickened distally in the zone of epidermis and muscle wall. Reproductive system (Fig. 69B) with single testis on the left and ovary on the right side. Common genital atrium present. The male copulatory apparatus (Fig. 69B) consists of a sclerotised stylet (a = 10.28µm, d = 32.8µm, b = 26.21µm, c = 11.6µm, and α = > 90 ), prostatic vesicle (55µm long), roundish seminal vesicle, and accessory glandular stylet (d = 30.5µm). Seminal and prostatic vesicle connected by a short intervesicular duct. The distal half of the vas deferens is expanded to a false seminal vesicle which is received by the 201

202 seminal vesicle. The prostatic vesicle, about 57µm long, passing into the hook-shaped stylet. The stylet distad tapering non-uniformly, is tube-like with proximal funnel, a = 10.28µm, and distal hooked end; the longitudinal axis of the stylet is abruptly bent behind its midst at an angle of greater than 90 (Fig. 49B). Distally, the stylet performs a semi-circle turn perpendicularly to the main distal axis; the distal end opens with an acute tip. The sclerotised accessory stylet (Fig. 49B) is a slightly curved, distad tapering, pointed tube. Measurements Fig. 69. Karlingia arrawarrensis sp. n. A. Dorsal view of slightly squashed specimen. B. Genital organs of slightly squashed specimen in greater amplification. of the accessory stylet are: a = 6.5µm, d = 30.1µm. The distal qblique opening lies subterminally on the convex side. The penial and glandular stylets protrude into a ciliated common genital atrium from dorsal and are directed postero-laterad and posteriad, respectively. Bursal organ with sclerotised apparatus (Fig. 69B). Sclerotised apparatus consists of mouth-piece, 27.4µm long, with two disc-like thickenings, 4.1µm in diameter, close behind funnel shaped distal end, indistinct mid-piece, 5.5µm long, and sperm tube, 98.3µm long. Common genital pore aboput 230µm distant from hind end. Etymology. The specific epithet refers to the sampling locality, i.e. Arrawarra, NSW, Australia. Karlingia barbelae sp. n. (Fig. 70) Type locality. Bulli, NSW, Australia, PCW; leg. Faubel, May Habitat. Eulittoral stygal, exposed sandy beach slope at 7m with moderately sorted medium sands, preponderance of grain size fractions finer than Md (-SkI) prevailing, marine. 202

203 Sediment parameters. 7m (25-30cm depth, GWL 23cm): Md μm = φ +1.16, QDI 0.77, SkI 0.17, POM 3.04%, Sal 32, marine. Description (m.l.s.). Body length up to 1.6mm by 0.13mm width, anterior end blunt, headshaped, posteriorly pointed, colourless in t.l. Eyes absent. Small rhabdites distributed rather evenly in distinct dense rows over the ventral and dorsal body. Anterior end with rhammite tracks running laterally from the anterior angles of the head to the area behind the pharynx where the rhammites are formed in glands. Cephalic glands not observed. Pharynx simplex poorly provided with pharyngeal glands, continues into long, small fore-gut. Cyclopoid copepod ingested in mid-gut (Fig. 70A). Reproductive system (Fig. 70B) with single testis at the left and ovary at the right side. Male system with penial and glandular stylet. Accessory stylet S-haped funnel, a = 9.43µm, decreasing gradually to a pointed tip (d = 41µm) with terminal opening. Penial stylet (a = 16.6µm, d = 57.6µm) represents a straight tube with distal semicircle, S-shaped turn in a Etymology. Named in honour of my wife Barbel. Fig. 70. Karlingia barbelae sp. n. A. Dorsal view of slightly squashed specimen. B. Genital organs of slightly squashed specimen. second plane at an angle of about 90 from the main axis; distal opening terminal. Prostatic vesicle enters proximal base of the style via a small prostatic duct. Prostatic and seminal vesicle combined by a long intervesicular duct. Vas deferens partly distended to a false 203

204 seminal vesicle through the development of masses of sperm. Female system with sclerotised bursal organ consisting of mouth-piece, 37.5µm long, mid-piece, and sperm-tube, 103µm long. Common genital opening present. Karlingia bulliensis sp. n. (Fig. 71) Type locality: Bulli, NSW, Australia, PCW; leg. Faubel, May Habitat. Eulittoral stygal, 3 to 10m of exposed sandy beach slope with moderately well and well sorted medium to fine sands, preponderance of grain size fractions finer than Md (-SkI) prevailing, marine. Sediment parameters. 3m (10-15cm depth, GWL 8cm): Md μm = φ +1.29, QDI 0.68, SkI 0.02, POM 1.56%; 10m (30-35cm depth, GWL 35cm): Md μm = φ +1.53, QDI 0.46, SkI 0.21, POM 0.79%. Description (m.l.s.). Body length up to 1.1mm by 0.2mm width, greatest width in the posterior body-half, with characteristic blunt macrostomid shaped fore-end and somewhat pointed posterior end (Fig. 71A). Brain bilobed. Cephalic glands open along the anterior margin to the exterior. Rhabdites distributed rather evenly in distinct rows over the ventral Fig. 71. Karlingia bulliensis sp. n. A. Dorsal view of slightly squashed specimen. B. Genital organs of slightly squashed specimen in greater amplification. C. male stylet turned around its longitudinal axis of about 180 with respect to identical the stylet depicted in B. and dorsal body; rhabdites in packets of 2 to 7 rods; packets measure between 15.2µm to 17.5µm in length. Rhabdites on the posterior end provided with adhesive function. In t.l. body 204

205 transparent, light yellowish, with intestine taking on light yellowish green to brown colouration when food is ingested. Eyes absent. Reproductive system (Fig. 71B, C) obviously not completely sexually matured. Testis and ovary single and obviously not completely developed, lying opposite to each other at caudal end of intestine. Male system with penial and glandular stylet (Fig. 71B, C). Accessory glandular stylet a slightly bow-shaped tube, d = 33.3µm, decreasing gradually to a pointed terminal opening; proximal opening subterminal (a = 6.8µm). Penial stylet represents a proximal funnel-shaped tube (Fig. 70B, C), a = 10.2µm, d = 28.91µm, and a distal S-shaped hook which is bent from the main axis at an angle of about 90 ; distance between base and first distal bend of the main axis 21.7µm (uprightly erected line on a). The prostatic vesicle is distally encased by the funnel shaped base of the male stylet. Seminal vesicle and vas deferens evidently not yet completely developed. Female system with sclerotised bursal organ consisting of mouth-piece, 33.5µm long, and mid-piece, 33.1µm long; sperm-tube absent. Common gonopore about 210µm distant from posterior end of body. Sperm tube absent and cement glands surrounding the common genital pore, not yet developed. Etymology. The specific epithet refers to the sampling locality, i.e. Bulli, NSW, Australia. Karlingia sp. Fize 1963 (Fig. 72) Locality. Golfe d Aigues-Mortes, Gulf of Lion, MED. Fig. 72. Karlingia sp. Fize A. dorsal view. B. bursal organ. C. penial and accessory stylets of male apparatus (after Fize 1963). Morphological notes. Body longish oval with rounded ends. Eyes present. Rhammite tracks open along anterior end of body (Fig. 71A). Reproductive system. Single testis on the right, ovary on the left. Male stylet apparatus multiform but elements evidently not clearly defined and assigned (Fize 1963 fig. 13d2). Bursal organ with sclerotised apparatus, the elements of which not exactly to assign (Fize 1963, fig. 13d1). Genus Acanthomacrostomum Papi & Swedmark, 1959 Diagnosis. Karlingiinae with endo-skeleton. Intestine without muscle ring. Testis and ovary single. Penis stylet simple; accessory glandular organ with stylet. Bursal organ with sclerotised apparatus consisting of mouth-piece, mid-piece, and sperm tubes; ductus spermaticus present. Epidermis with insunk nuclei. Adhesive papillae only ventrally. Type of the genus: Acanthomacrostomum spiculiferum Papi & Swedmark, 1959 Remarks. The composition of the spicules of the endo-skeleton is most probably of calcareous material (Papi & Swedmark, 1959, p. 235; Ax 1971, p. 7; Rieger & Sterrer 1975, p. 253). A definite answer cannot be given at present. Only known is, however, spicules are diluted in mineral acids and Bouin (histological fixative) (Ax 1971, Rieger & Sterrer 1975). 205

206 Acanthomacrostomum spiculiferum Papi & Swedmark, 1959 (Plate XXII: J-O) Type locality. Pointe de Bloscon, Roscoff, Bretagne, France, English Channel, ANE; types: deposition not reported. Habitat. Sub-and eulittoral benthal, coarse shelly sandy sediments, down to 65m water depth, marine. Geogr. distribution. ANE: Irish Sea (Northern Ireland), English Channel (France: Roscoff); IO:? Bay of Bengal (India: Waltair Coast) (Boaden 1966, Bocquet 1971, Rao & Ganapati 1968, Rao 1969). Morphological notes (Plate XXII: J-K). Body length up to 1.0mm, rounded anteriorly and posteriorly, greatest width in posterior body-half. Spicules of the endo-skeleton (Plate XXII: L) rod-shaped, 50-60µm long, 3-4µm wide, tapering off towards both ends, and covered with small irregular wart-like thickenings. In the posterior and anterior part of the body spicules curved, following the form of the body. Adhesive glands restricted to along ventral margin and to ventral area of anterior and posterior body-end. Brain roundish mediately penetrated by rhammite tracks. Epithelium with adenal nuclei. Eyes and rhabdites absent. Pharynx simplex with ring of pharyngeal glands. Besides rhabdites entering only the area of ring of pharyngeal glands, roundish granules, 1µm in diameter, occur both in this area and further caudal of pharynx. Rhopalura sp., Orthonectida, parasites in A. spiculiferum. Reproductive system (Plate XXII: J, M, N) with common genital atrium. Single testis on the left and ovary dorso-medially in posterior body-half. Male stylet hook-like, about 70µm long (Plate XXII: N); stylet of accessory glandular organ 80µm long, distally tapering. Proximally, stylet encases prostatic vesicle. Bursal organ with mid-piece, 34µm long, and mouth-piece, 40µm long, extend into spermatic duct; disk-like thickenings of mouth-piece present. Sperm tubes absent. Oviduct extend caudad from last oocyte into genital atrium. Bursal canal ciliated, connects genital atrium with dorso-lateral bursal organ. Remarks. Ax (1971) suggested that Acanthomacrostomum spiculiferum found by Rao and Ganapati on Waltair Coast, India, might be Acanthomacrostomum gerlachi Ax, Acanthomacrostomum gerlachi Ax, 1971 (Plate XXII: P-S) Type locality. Island Wadewaru, Fadifollu Atoll, Maldives, IO; leg. S.A. Gerlach, April 1958; types: deposition not recorded. Habitat. Eulittoral benthal, coarse sand, marine. Geogr. distribution.? IO: Bay of Bengal (India: Waltair Coast) (Rao & Ganapati 1968, Rao 1969). Morphological notes (Plate XXII: P). Body length up to 0.62µm (m.f.s.), anterior and posterior ends bluntly tapered, triangular, posterior end with adhesive papillae. Eyes absent. Peripheral parenchyma with endo-skeleton. Reproductive system (Plate XXII: Q, R) with single ovary; testis not recorded. From ventral common gonopore the genital atrium arises dorsad, into which the ejaculatory duct and bursal organ enter via the bursal canal from anterior and the glandular stylet from dorsoposterior; bursal organ dorsal of ejaculatory duct. Male complex consisting of seminal vesicle, prostatic vesicle, penial stylet, and accessory glandular organ with glandular stylet. Glandular stylet 50µm long, penial stylet 50-52µm in length. Sclerotised apparatus of bursal organ composed of mouth-piece with two disk-like thickenings, oval-shaped mid-piece sclerotically reinforced, and 85µm long sperm tube. Bursal canal ( Bursastiel after Ax 1971, p. 302) sclerotically reinforced and surrounded by strong circular muscle fibres. 206

207 Remarks. As to the geographic distribution of A. gerlachi see Acanthomacrostomum spiculiferum Papi & Swedmark, Acanthomacrostomum sp. (Figs 73-74) Type locality. Bulli, New South Wales, Australia, Tasman Sea, PCW; leg. Faubel, May 25 th, Habitat. Eulittoral benthal and stygal, 1m (lb) to 10m (ub) of exposed sandy beach slope with well sorted to moderately sorted medium to fine sands, preponderance of finer grain size fractions than Md dominantly prevailing (-SkI), marine Sediment parameters. Range from 1m (lb) to 10m (ub, GWL 35cm) Md μm = φ to 2.03, QDI 0.46 to 0.87, SkI 0.21 to +0.08, POM 0.79% to 3.04%. Geogr. distribution. PCW: Tasman Sea (New South Wales: Kioloa). Fig. 73. Acanthomacrostomum sp. Microphotograph of living specimen. A. anterior body-half. B. posterior body-half. anterior end to anterior border of pharynx 90.3µm. Description (m.l.s.). Body length up to 0.55mm by 0.05mm width, terminally rounded, colourless in t.l. Subepidermal spicule 25.5µm long. Distance from Bulli 2 - ind. (tot.): lwl cgt m 10m 5m 3m 1m 0m 1m 3m 5m 7m 10m lb sh ub Fig. 74. Abundance of Acanthomacrostomum sp. along a profile of an exposed sandy beach from the warm temperate clime of the eastern coast of Australia. Each subsample represents a sample size of 25cm 3 sediment (5cm² surface, 5cm depth) (abbreviations see Fig. 45). 207

208 Reproductive system with bilateral testes and single ovary. Seminal bursa pass into distal vagina. Distance from posterior end to male gonopore 111µm. Ecological notes. Acanthomacrostomum sp.could be find along the whole exposed sandy beache in the warm temperate clime of the eastern coast of Australia off Bulli (Fig. 74). The species favours deeper sediment layers of sandy beaches. The greatest density of abundance (Fig. 74) was recorded between 5 and 7m of the upper beach in and directly above the coastal groundwater table. Genus Myozonaria Rieger, 1968 Diagnosis. Karlingiinae with muscle-ring on gut. With single testis and ovary. Stylet complicated, based on foldings and torsions. Accessory organ with glandular stylet. Bursal sclerotised apparatus present. Type of the genus: Myozonaria bistylifera Rieger, 1968 Remarks. The genus Myozonaria is mainly characterised by the muscle ring on gut and single ovary. Based on these features, the species deviate from the species of the genera Karlingia and Acanthomacrostomum. At present to the genus Myozonaria belong five species. Myozonaria rohdei is included in this genus on the basis of the muscle ring on gut, the single ovary, and the accessory glandular stylet being not merged with the penial stylet. The new species differ mainly in the feature as follows: straight tubular tube of stylet being distally splitted, bursal organ with accessory sperm-tube, rhammite tracks extending from posterior end to frontal margin, epithelial rhabdites, and black eyes. Key to the species of Myozonaria. 1 species without eyes 2 - species with eyes Myozonaria rohdei 2 male stylet tube-shaped, distally hooked or provided with distal thickenings 3 - male stylet complicate, longer than 100µm Myozonaria bistylifera 3 stylet with distal thickenings 4 - stylet with distal pointed hook Myozonaria ascia 4 stylet without ring-like thickening 5 - stylet with ring-like thickening, ovary and testis opposite Myozonaria jenneri 5 testis and ovary on the right body-side Myozonaria arcassonensis sp. 1 - testis and ovary on the left body-side Myozonaria arcassonensis sp. 2 Myozonaria bistylifera Rieger, 1968 (Plate XXI: C-G) Type locality. Baia Lone, Rovinj, Croatia, Gulf of Venice, Adriatic Sea, MED; leg. April 1965, Aug. 1967; types: Habitat. Sublittoral benthal, sandy sediments grown with seagrasses or Posidonia sp., down to 10m water depth, marine. Geogr. distribution. MED: Adriatic Sea (Croatia: Valdibora, Dalmatian coast near Dubrovnik); Gulf of Lion (France: Banyuls-sur-mer, Marseille area: Ile de Plane, Archipel von Riou) (Rieger 1971c). Morphological notes (Plate XXI: C). Body length up to 4.0mm by 0.3mm width. In t.l. body transparent but slightly greenish rhabdites give a greyish tinge; in i.l. body whitish with 208

209 brownish green contrasting gut, larger oocytes brown. Eyes absent. Sensitive tactile bristles at anterior and posterior body-end. Caudal sensitive organ with ten club-shaped ends. Adhesive papillae around body. Frontal glands and rhammite glands present, which open at the anterior tip of body. Four rhammite tracks, two at medio-dorsal and two at medio-ventral, extend anterior to brain rostrad. Epidermis intra-epithelial nuclei but anterior end with adenal nuclei; dermal glands intra-epithelial and adenal; numerous adenal rhabdites present. Body muscle wall structured as usual. Dorso-ventral muscle fibres well developed. Parenchyma strongly vacuolarised. Protonephridia not observed. Brain dispatches two lateral main nerve cords and innervate fore-end and nerve ring of pharynx simplex above pharyngeal gland ring. Intestine with muscle-ring. Food diatoms. Reproductive system (Plate XXI: D-G) with single testis and oogonia of ovary in anterior body-half; testis and ovary on the right. From ventral common gonopore the ciliated genital atrium arises rostro-dorsad, into which the ejaculatory duct and the accessory glandular organ enters from left, the oviduct from ventro-lateral, and the bursal canal enters from dorsolateral. The bursal canal joins the atrium with the bursal organ lying caudal of the ovary. Cement glands excrete into the distal part of the genital atrium. Male copulatory apparatus (Plate XXI: D, E) located caudal of the genital atrium on the left side of body, with seminal vesicle, prostatic vesicle (200µm long m.f.s.), complicate penial stylet (averaging 172µm in length), accessory glandular organ, and glandular stylet (averaging 98µm in length). The accessory glandular organ lies anteriorly of gential atrium on the left. Seminal vesicle and prostatic vesicle joined by a short intervesicular duct, walled with strong circular muscle fibres. Ejaculatory duct in early developmental phase ciliated. Muscular part of accessory glandular organ 70-80µm long. Distally, prostatic vesicle encased by the proximal tube of the penial stylet. Accessory glandular organ muscularly walled, with central small duct which is surrounded by glandular cells. Glandular duct probably ciliated. Glandular stylet distally hooked. Bursal organ anterior to genital atrium, opens into the latter via a non-ciliated bursal canal. Bursal apparatus with mouth-piece, 40-66µm long with two disc-like thickenings, and mid-piece forming a panel with caudal thickening, 33-47µm. Sperm tubes 70µm long. Spermatic duct indistinct. Bursal canal present. Myozonaria arcassonensis Rieger, 1971 (Plate XXI: H-L) Specimen 1 (Arcachon form) Type locality. Bassin d Arcachon, France, Bay of Biscay, ANE; leg. P. Ax, Sept. 1954; types not deposited. Habitat. Eulittoral benthal, in fine to medium sand, marine. Morphological notes. Body length up to 2.0mm, yellowish brown in t.l. Eyes absent. Epidermis with rhabdites and roundish glands. Rhammite tracks present. Pharynx simplex with ring of pharyngeal glands. Gut extends caudad to the level anterior to bursal apparatus. Observations to muscle-ring on gut absent. Reproductive system (Plate XXI: H-I) with single testis on the right side of body. Ovary on the left side of body. Oviduct not recorded. False seminal vesicle indistinct but seminal vesicle distinct; intervesicular duct present. Prostatic vesicle passes into stylet; stylet distally somewhat thickened (Plate XXI: H); total length 45µm. Accessory gland with glandular stylet (Plate XXI: I). Bursal organ sclerotised, consisting of sperm tube, mid-piece and mouth-piece as drawn in Plate XXI: L. Total length of sclerotised apparatus 80µm. Bursal canal not observed. 209

210 Specimen 2 (Marseille form) Type locality. Cap Canaille, Bay of Cassis, Gulf of Lion, France, MED; leg. M. Brunet, Oct. 1966; types not deposited. Habitat. Eulittoral benthal, in fine to medium sand, marine. Morphological notes. Body length up to 1.6mm, Eyes absent. Anterior body with rhammite tracks. Pharynx simplex with ring of pharyngeal glands. Gut extends caudad to the level anterior to bursal apparatus. Observations to muscle-ring on gut absent. Reproductive system (Plate XXI: J-K) with single testis on the left side of body. Ovary and oviduct not recorded. Vas deferens dilates to a prominent false seminal vesicle. True seminal vesicle and, therefore, intervesicular duct not observed. Prostatic vesicle passes into stylet; stylet distally somewhat thickened (Plate XXI: J); total length 35µm. Accessory gland with glandular stylet, about 70µm in length, re-drawn in Plate XXI: K. Bursal organ sclerotised, consisting of sperm tube, mid-piece and mouth-piece as drawn in Plate XXI: L. Total length of sclerotised apparatus 100µm. Bursal canal not observed. Cements glands discharge into genital atrium. Remarks. The establishment of the species Myozonaria arcassonensis is based on sketches made by P. Ax on living specimens sampled in the Bassin d Arcachon, and on sketches made by M. Brunet on living specimens sampled in the Bay of Cassis, Marseille. Though a relative conformity exists between the outline of the stylets and the sclerotised elements of the bursal organ, Rieger (1971b) believed it could be evident that specimen 1 and specimen 2 are different valid species because the proportions and measurements of the sclerotised elements display distinct differences. Myozonaria ascia Sopott-Ehlers & Schmidt, 1974 (Plate XXI: S-T) Type locality. Santa Cruz, IX, 5b), Galapagos Islands, PSE ; leg. P. Schmidt, Febr March 1973; types: deposition not recorded. Habitat. Sub- and eulittoral benthal, sandy sediments, marine. Morphological notes. Body length up to 0.6mm, with anterior end smaller rounded than posterior end being broadly rounded. Rhammite track medially piercing brain, run to anterior margin of body; half-way between brain and frontal border, track split fan-like to open along anterior margin to the exterior. Epithelium with adenal rhabdite bundles of 4-5 rods (4-6µm long). Adhesive glands not observed. Hind end with sensory bristles. Intestine with muscle ring on gut. Reproductive system (Plate XXI: S-T) with single testis and ovary on the right body-side. Testis lies anterior to muscle ring on gut, ovary farther behind the latter. Male copulatory apparatus with seminal vesicle and prostatic vesicle joined by a short intervesicular duct, and distal stylet. Both the vesicular organs walled with circular muscle fibres. Male stylet, 55µm in length, slightly bent and distally with pointed hook directed proximad. Glandular organ, 40µm in length (m.s.f.), covered with circular muscle fibres, crossed by ciliated glandular duct. Glandular stylet, about 40µm long (m.f.s.), extends into ciliated common genital atrium. Female system with bursal organ joined via bursal canal with common genital atrium. Sclerotised bursal apparatus with mouth-piece, 25-30µm long, mid-piece with longitudinal ridge, and sperm tube, 80µm in length. Mouth-piece with two distal thickenings. Myozonaria falcis Sopott-Ehlers, 1976 (Plate XXI: P-R) Type locality. Plage Pereire, Bassin d Arcachon, Bay of Biscay, ANE; leg. Sept. 1974; types: deposition not recorded. 210

211 Habitat. Sublittoral benthal, sandy sediments, marine. Geogr. distribution. ANE: English Cannel (France: Bretagne, Ile de Callot) (Sopott-Ehlers 1976). Morphological notes. Body length up to 2.0mm, yellow-brown in t.l., with blunt frontal end; posterior end rounded with adhesive glands and with terminal ciliary tuft. The caudal adhesive organ belonging to the ciliary tuft (cf. Rieger & Tyler 1974), could not be observed in serial sections as well as in squashed preparation. Rhammite tracks separately open along frontal margin. Muscle ring on gut in second body-half. Eyes absent. Cleft-shaped mouth short behind brain opening. Mouth surrounded by rhabdite glands. Reproductive system (Plate XXI: P-R) with single testis and ovary on the right side. Testis just anterior to muscle ring on gut and ovary immediately behind testis. Vas deferens halfway caudad, dilates to false seminal vesicle and somewhat further caudad of the latter the vas deferens opens into the seminal vesicle. Seminal vesicle and prostatic vesicle joined by an intervesicular duct. Prostatic vesicle with two kinds of granular secretion. A short prostatic duct extends into proximally expanded opening of male stylet. Male stylet 60-70µm in length. Glandular stylet, 60-70µm long, connected with muscular vesicle, µm long. Sclerotised apparatus of bursal organ with mouth-piece, 20-25µm, mid-piece, and single sperm tube, 135µm long. Mouth-piece with two characteristic distal thickenings. Mid-piece consists of circular plate and pectinately toothed projection. Myozonaria jenneri Rieger & Tyler, 1974 (Plate XXI: M-O; Fig. 5A) Synonyms. Myozonaria sp. Rieger, 1971; p. 206, 228, nom. nud. Type locality. Atlantic side of Bahia Honda Key, Florida Keys, USA, ANW; leg. Rieger, May 1971, types: AMNH-NY, Habitat. Sublittoral benthal, calcareous sand of medium grain size, down to 40m water depth, marine. Morphological notes. Body length up to 1.0mm, colourless, with typical frontal end; posterior end slightly pointed; tip of pointed hind end with terminal ciliary tuft. Caudal sensory organ unpaired, consisting of nine bulb cells and canal through which the cilia emerge through the external pore forming the ciliary tuft (cf. General Account p. 10, Fig. 4). Paired rhammite tracks separately open along frontal margin fan-like, the glands of which lie in second body-half anterior to muscle ring on gut. Eyes absent. Lateral nerve cords insunken below circular muscles of body muscle wall. Parenchyme weakly developed. Pharyngeal glands open via distal pharyngeal gland ring in the mouth region. Gut extending caudad posterior to genital atrium. Reproductive system (Plate XXI: M-O) with single testis and ovary. Testis ventro-lateral at level of muscle ring on gut in right body-side. Ovary on left body side. Male copulatory apparatus with seminal vesicle, prostatic vesicle containing two kinds of secretory granules, and penis stylet, 50-55µm long. Shape of stylet with ring-like thickening in distal region and with distalmost thickenings and folds. Accessory glandular organ muscularised, proximally entered by extravesicular glands in common pore. Stylet of accessory glandular organ, 30-40µm long, slightly curved and distally pointed. Sclerotised apparatus of bursal organ consisting of mouth-piece, 20-25µm long, middle piece, a simple plate, approximately 30µm long, and sperm tubes, about 100µm long. Spermatic duct present. Myozonaria rohdei sp. n. (Fig. 75) 211

212 Locality: Kioloa, NSW, Australia, PCW; leg. Faubel, May 1998; types: ZIM-H, V (CD- ROM). Habitat. Eulittoral benthal, 15m exposed sandy lower beach with well sorted fine sands, preponderance of grain size fractions finer than Md (-SkI) prevailing, marine. Sediment parameters. 15m (0-5cm depth, hwl 22m): Md μm = φ +1.63, QDI 0.49, SkI 0.13, POM 0.66%. Description (m.l.s.). Body length up to 1.4mm by 0.2mm width, anterior body-end rounded, posterior body-end pointed, colourless, black eyes at dorso-posterior border of brain 185µm distant from anterior margin (Fig. 75A). Tracks of rhammites extend from the posterior end of body to the anterior margin where the rhammites are released to the exterior. Length of rhammite rods varied between 11µm and 13µm. Cephalic glands absent. Epithelial rhabdites, abouth 9µm in length, composed of up to 5 rods, irregularly distributed over the body surface. Length of gut about 585µm; muscle ring on gut at about 173µm anterior to hind end of gut. The posterior end of the gut is connected with the female genital system via a ductus genito-intestinalis being 87µm long. Fig. 75. Myozonaria rohdei sp. n. A. Dorsal view of slightly squashed specimen. B. Genital organs of slightly squashed specimen in greater amplification. Reproductive system (Fig. 75B) with single testis and ovary. Male stylet tube-shaped (Fig. 75B) (d = 80µm, a = 16.2µm) with sides paralleled up to the level of the distal splitted part. In 212

213 dorsal view, the dorsal splitted half is slightly bent upwards with distal blunt end; the ventral half is distally rounded. The splitted part of the stylet forms the terminal opening. Turning the stylet about 90 around its axis, the distal splitted end reveals a few inner lateral folds forming the distal ejaculatory duct. Glandular stylet (Fig. 75B), 105µm long, a slightly S-shaped tube with proximal funnel, a = 9.82µm, and distal pointed tip (Fig. 74B). Female system with sclerotised bursal organ consisting of spiralled sperm tube forming 7 smaller and greater spirals, 42µm long, mid-piece 14.68µm (longest extension), mouth-piece, 14.68µm long, with two distal disc-like thickenings (each 8.87µm in diameter), and accessory sperm-tube. Accessory sperm-tube straight, 47.74µm long, with proximal opening of 5.8µm in diameter and distal oblique terminal opening 3.8µm in diameter (Fig. 75B). The bursal canal surrounded by glands, enters the common genital atrium from behind. Etymology. The specific epithet is dedicated to Prof. Dr. Klaus and Eveline Rohde, Armidale, Australia, being all the time greatly hospitably. Nomina nuda Myozonaria americana Rieger, 1971 Type locality. Off Beaufort, N W, North Carolina, USA, ANW; leg. R.M. Rieger, April 1970; types: deposition not recorded. Myozonaria carolinensis Rieger, 1971 Type locality. Off Beaufort, N W, North Carolina, USA, ANW; leg. R.M. Rieger, April 1970; types: deposition not recorded. Myozonaria mediterranea Rieger, 1971 Type locality. Unknown. Myozonaria microstyla Rieger, 1971 Type locality. Off Beaufort, N W, North Carolina, USA, ANW; leg. R.M. Rieger, April 1970; types: deposition not recorded. Remarks. The above species nom. nud. of the genus Myozonaria were listed by Rieger (1971b, p. 249) as being in press. In reality, that was made preliminary because the species were never published until now. In the publication on Bradynectes sterreri (1971a), Rieger presented the locality of the North American species on page 206. However, the locality of Myozonaria mediterranea remains unknown. Genus Paramyozonaria Rieger, 1971 Diagnosis (emend n.). Karlingiinae with muscle-ring on gut. Single testis and bilateral ovaries. Penial stylet with distal folds. Accessory glandular organ without glandular stylet. Sclerotised apparatus of bursa with long mouth-piece and large mid-piece, the latter representing a complicated folded sheath. Type of the genus and only species: Paramyozonaria simplex Rieger, 1974 Paramyozonaria simplex Rieger & Tyler, 1974 (Plate XXII: A-B) Synonymy. Paramyozonaria simplex Rieger, 1971; p

214 Type locality. New River Inlet, N Carolina, USA, ANW; leg. Rieger, July 1971; types: AMNH-NY, Habitat. Sublittoral benthal, medium to fine sand, marine (?), brackish. Geogr. distribution. ANW: USA (N Carolina: Bogue Banks); Gulf of Maine (Canada: New Brunswig: New River Beach, Carrying Cove) (Ax & Armonies 1987). Morphological notes (Plate XXII: A). Body length up to 0.7mm, rounded anterior and posterior end, colourless. Posterior end of body with long bristles and long terminal ciliary tuft. Eyes present. Paired rhammite tracks separately open along frontal margin fan-like, the glands of which lie in second body-half anterior to muscle ring on gut. Rhabdites and glands of adhesive papillae adenal; rhabdites scattered throughout whole body. Caudal sensory organ (cf. above General Account p , Fig. 5) paired, consisting of cluster of bulb cells, 3 cells on the left and 5 cells on the right, and canal. Clear ciliary tufts not observed, however, the organ is believed to be connected with cilia, 4 to 5 times the length of regular sensory hairs, on the caudal body-end. Pharyngeal glands open into distal pharyngeal gland ring. Gut extending caudad anterior to genital atrium. Reproductive system (Plate XXII: B) with single testis and bilateral ovaries. Testis just behind pharynx on the left side. Sperms 90µm long. Male copulatory apparatus with seminal vesicle, prostatic vesicle and distal stylet. Distal prostatic vesicle encased by proximal stylet. Penial stylet averaged 55µm (Canadian specimens 66µm long after Ax & Armonies 1987), with characteristic thickenings and folds distally. Bursal organ with sclerotised apparatus consisting of mouthpiece, 10µm long, middle piece, complex folded, and sperm tubes, 85-90µm long; middle piece connected with special muscle fibres to inner opening of bursal canal. Riegerizonaria gen. n. Diagnosis. Karlingiinae with muscle-ring on gut. Single ovary and testis. Penial stylet with distal folds. Accessory glandular organ without glandular stylet. Sclerotised apparatus of bursa with long mouth-piece and large mid-piece, the latter representing a complicated folded sheath. Type of the genus: Paramyozonaria riegeri Sopott-Ehlers & Schmidt, 1974 Etymology. In honour of Prof. Dr. R.M. Rieger; combination of his name with the name of the genus Myozonaria. Remarks. The establishment of the new genus Riegerizonaria is based on the development of bilateral ovaria. The development of bilateral ovaries within the Dolichomacrostomidae is hardly developed and only present in the less species rich genera Austromacrostomum, Cylindromacrostomum, and Megamorion. Riegerizonaria riegeri (Sopott-Ehlers & Schmidt, 1974) comb. n. (Plate XXII: C-G) Synonymy. Paramyozonaria riegeri Sopott-Ehlers & Schmidt, 1974; p , figs 3-5. Type locality. Santa Cruz, XIX, 5c, Galapagos Islands, PSE ; leg. P. Schmidt, Febr to March 1973; types: deposition not recorded. Habitat. Eu- and sublittoral benthal, sandy sediments, down to 2m water depth, marine. Geogr. distribution. PSE: Galapagos Islands (Fernandina: I,3); ASW: Caribbean Sea (British Honduras: Carrie-Bow Cay) (Rieger 1977). 214

215 Morphological notes (Plate XXII: E). Body length up to 1.0mm, with anterior end smaller rounded than posterior end being broadly rounded. Rhammite track medially piercing brain, split into two tracks and run to anterior margin of body to open along anterior margin to the exterior fan-like. Epidermis with numerous adenal rhabdite bundles of rods, distributed over dorsal and ventral surface. Body muscle wall structured as usual. Adhesive glands not observed. Hind end with sensory bristles. Mouth with nerve ring. Pharynx with pharyngeal glands and adenal rhabdite-glands. Intestine with muscle ring on gut about at level of the beginning of the second body-third; intestinal epithelium ciliated and with Minotian cells. Reproductive system (Plate XXII: C-G) with single testis and ovary on the right body-side. Testis lies anterior to muscle ring on gut, ovary farther behind the latter. Vas deferens distend half-way between testis and seminal vesicle to false seminal vesicle. Male copulatory apparatus with seminal vesicle and prostatic vesicle joined by a short intervesicular duct, and with distal stylet. Both the vesicular organs walled with circular muscle fibres. Prostatic vesicle crossed distally by widely spaced duct. Ciliation of this duct could not be analysed distinctly. Male stylet, 80µm in length, consisting of several interleaved tubes. Peripherally, stylet one-sided with triangular tab, 20µm in diameter, bearing 8-12 thorns of 15-25µm length. A collar being 45-50µm high, surrounds further, two strongly folded elements. The stylet lies in a distal genital duct lined with faint, squamous epithelium, and is surrounded at its basis with circular muscle fibres. Female system with bursal organ joined via non-ciliated bursal canal with ciliated common genital atrium. Sclerotised bursal apparatus with mouthpiece, 27-30µm long, mid-piece, 30-35µm long, and sperm tube, 140µm in length. Mouthpiece with two distal thickenings. Mid-piece rostrally provided with 5-7µm long spikes whereas one of them is bifurcated; laterally numerous teeth are attached. A thick, slightly curved sclerotised process, 10µm long, arises from mid-piece to which the sperm tube is attached; at the same level, the mouth-piece is affixed. Bursal organ with syncytial tissue containing degraded nuclei and several free spaces. The entrance of the bursal canal into the bursal organ is surrounded by cyanophilous glands. Oviduct with nucleate epithelium, extends into anterior genital atrium just above cement glands which surround common gonopore. Remarks. The length of stylets of the populations from British Honduras ranged between 70µm and 75µm (Rieger 1977). According to Fig. 4E in Sopott-Ehlers & Schmidt 1974 (photo in squashed preparation), the stylet complex is obviously composed of a peripheral collar enclosing proximally an interior stylet with oblique opening (looking like a triangular plate) bearing on the apical border 8-12 thorns of different lengths, and distally two strongly folded elements. The description given by Sopott-Ehlers & Schmidt (1974) of the peripheral triangular tab (see above) looks abnormal. Riegerizonaria portmacquariensis n.sp. (Fig. 76) Locality: Shelly Beach, Port Macquarie, (31 o 27 S, 153 o 55 E), NSW, Australia, PCW; leg. Faubel, Sept Habitat. Eulittoral stygal, 10m exposed sandy beach slope with well sorted fine sands, preponderance of grain size fractions larger than Md (+SkI) prevailing, marine. Sediment parameters. 10m (20-25cm depth, GWL 40cm): Md μm = φ +1.84, QDI 0.43, SkI +0.04, POM 0.42%, Sal 35. Description (m.l.s.). Body length up to 2.1mm by 0.12mm width, extremities rounded, in t.l. colour dirty yellowish grey (Fig. 76A). Small muscle ring on gut 370µm distant from mouth, about in mid-gut. Cephalic glandular ducts extend from frontal end posteriad to the level behind pharynx passing into cephalic glands. Eyes absent. Oval rhabdites present, arranged rather evenly in distinct rows. Rhammite tracks and glands absent. Rear body-end provided with adhesive glands. 215

216 Reproductive system (Fig. 76B) with single testis and ovary. Male stylet represents a funnel-shaped (a = 20.05µm, d = 31.9µm) with distal bend (α > 90 ); the stylet distad of the bend looks very complicated (Fig. 76B). The exact opening is not to ascertain. Funnel-shaped proximal base of stylet encases ducts of extravesicular prostatic glands forming centrally the prostatic duct. The globular prostatic vesicle contains numerous small, fine-grained vesicles. Prostatic and semial vesicle joined via long intervesicular duct. Vas deferens convoluted, distended to a false seminal vesicle when immensely sperm is produced. Female system with sclerotised bursal organ. Sperm tubes absent. Mouth piece, 15.3µm long, with two disc-like thickenings; mid-piece diagonally measured 24.2µm long. Common gonopore into which cement glands enter, present. Etymology. The specific epithet refers to the sampling locality, i.e. Port Macquarie, NSW, Australia. Fig. 76. Riegerizonaria portmacquarienis sp. n. A. Dorsal view of slightly squashed specimen. B. Genital organs of slightly squashed specimen in greater amplification. 216

217 Species incertae sedis Paramyozonaria bermudensis Rieger 1977 (Plate XXII: H-I) Type locality. Tobacco Bay, Bermuda, ANW; leg. July 1973; types: AMNH-NY, Habitat. Sublittoral benthal, sandy sediment, down to 2m water depth, marine. Geogr. distribution. ASW: Bermuda (Tuckerstown Cove); Straits of Florida (Bahia Honda Key) (Rieger 1977). Morphological notes. Body length up to 1.5mm by 0.2mm width (in region of ovary). Eyes absent. Reproductive system. Stylet length of specimen from Tuckerstown Cove 91µm, which was only slightly larger than any of the measurements in the Tobacco Bay populations (Rieger 1977, p. 208); length of specimen from Florida Keys 79µm. Sclerotised stylets of specimens from Bermuda and Florida see Fig. x. Nomina nuda. Paramyozonaria bruneti Rieger, 1971 nom. nud. Remarks. The knowledge of this species is very meagre. Rieger (1971b, p. 249) presented only a list of species nomina nuda which should be in press. Sparse knowledge on the anatomy is to find in Sopott-Ehlers & Schmidt (1974a, p ). The distal part of the stylet of P. bruneti displays great similarity in the outline and detailed construction with P. bermudensis Rieger, 1977 and P. riegeri Sopott-Ehlers & Schmidt, Absence of the spikes in the middle part of the stylet discerned P. bruneti from both the other species. Paramyozonaria rosacea Tyler, 1977 nom. nud. Type locality. New River, 1.5 miles from inlet, south shore, North Carolina, USA, ANW. Habitat. Sublittoral fringe, benthal, medium to fine sandy sediment, marine. Morphological notes not presented. Subfamily Bathymacrostominae Faubel, 1977 Diagnosis. Dolichomacrostomidae with stylet, prostatic vesicle, and seminal vesicle. Accessory glandular organ absent. Female system with atrial bursa and characteristic bursal sperm tube with distal disk-like thickening and mid-piece. Single testis present. Gonopores separate. Free-living, marine. Type of the subfamily: Bathymacrostomum Faubel, 1977 Genus Bathymacrostomum Faubel, 1977 Diagnosis. Dolichomacrostominae with characteristics of the subfamily. Bilateral ovaries and single testis present. Type of the genus: Bathymacrostomum spirale Faubel, 1977 Bathymacrostomum spirale Faubel, 1977 (Plate XXIII: A-C) 217

218 Type locality. Fladen Ground, N; E, North Sea, ANE, leg. Aug. 1975; type: not deposited. Habitat. Sublittoral benthal, mud to silty-clay sediments, 118m water depth, marine. Morphological notes (Plate XXIII: A). Body length up to 0.7mm, frontal end more or less truncate, posterior end bluntly pointed without adhesive glands, in i.l. colourless but gut and eggs contrasting whitish. Eyes absent. Rhammite rods and glands in the anterior body-third, rhabdites present. Brain crescentic, anterior to pharynx simplex. Intestine with nematodes and harpacticoids as food. Reproductive system with bilateral ovaries and single testis caudal of germinative zone of right ovary. Atrial bursa with sclerotized appendage consisting of distal disk-like thickening, mid-piece and sperm tube. Male copulatory complex simple with spiralled stylet, prostatic vesicle and seminal vesicle. Accessory glandular organ lacking. Male and female sclerotised copulatory elements see Plate XXIII: B,C. Genus Mactanea gen. n. Diagnosis. Bathymacrostominae with single testis and single ovary. Male stylet and glandular stylets combined to a common organ passing into the prostatic vesicle. Accessory glandular organ absent. Type of the genus: Mactanea padinensis sp. n. Etymology. The generic name refers to the type locality Mactan Island, Cebu, Philippines. Mactanea padinensis sp. n. (Fig. 77) Type locality. Mactan Island, Cebu, Philippines; leg. Faubel, March 1981; types: not deposited. Habitat. Tidepools of eulittoral coral rocky flat in the Padina belt, marine. Etymology. The specific name refers to Padina belt of the eulittoral coral flat of Mactan Island where the species was found. Description. Length of body of living sexually mature specimens up to 2.0mm, when extended and gliding; fore-end up to 0.12mm width, gradually widing to mid-body, from here the body widens abruptly to a maximum width of up to 0.26mm in posterior body. Outline of body with characteristic macrostomid like anterior blunt end; posterior end roundishly truncated, provided with adhesive glands (Fig. 77A). Around margin weak sensory hairs of varying length and stiffness present. In i.l., body grey with dark grey contrasting gut and oocytes. Crescentic brain about 250μm (m.l.s.) distant from anterior margin. Rhammite glands open ventro-frontally to the exterior along the anterior margin of body. The cells of which extend posteriad up to the level of the pharynx simplex. Rhabdites distributed in longitudinal rows over the dorsal and ventral body surface. Digestive system with pharynx simplex, pierced by extrapharyngeal glands, and ciliated intestine. The intestine extends caudad to the left posterior part of body next to the testis. Mouth behind brain, 350μm (m.l.s.) distant from anterior end. Excretory system not observed, probably absent. The species is a predator on Nematoda, Harpacticoida and Turbellaria as well. Reproductive system (Fig. 77A, B). Common gonopore about 300 μm (m.l.s.) distant from rear body-end. Male and female system characteristically dolichomacrostomid-like. It consists of a single testis, vas deferens, seminal vesicle, prostatic vesicle, and a male stylet which 218

219 projects into the common genital atrium. Stylet complex complicate, Fig. 77B, total length d = 110μm, proximal opening a = 33μm in diameter, encasing the distal portion of the prostatic vesicle. The stylet complex is composed of a central tube being distally S-shaped curved; the distal curvation tapers to a terminal, pointed opening. Four smaller curved accessory glandular stylets branch off from the basis of the central penial stylet along the median concave side. All the accessory stylets and penial stylet are surrounded by a sclerotised sheath which is cut in along the concave side of the penial stylet, the exception being the proximal base of the sheath which ringlike closed; from here the slit of the sheath widens gradually to a distal, semicircle sheath. The female system (Fig. 77A, B) consists of a single ovary and a dolichomacrostomid-like bursal organ. The ovary lies next to the testes on the right side in the last third of body, generating caudad three oocytes. Bursal organ, kidney-shaped, provided with a sclerotised apparatus. The sclerotised apparatus consist of a distal, sclerotised tube, mid-piece, mouthpiece with two disk-like thickenings, and a separate sperm-tube; the distal thickening of the mouth piece is joined to the funnel-shaped spermatic duct (Fig. 77C). Sperm-tube with a single disk-like thickening; the distal end lies free in the bursal organ. Fig. 77. Mactanea padinensis sp. n. A. Dorsal view of a squashed specimen. B. Bursal organs. C. Male copulatory organ in quashed preparation. 219

220 Remarks. The members of the Dolichomacrostomidae are characterised by a typical bursal organ consisting of distinct sclerotised pieces. In this respect the new species Mactanea padinensis proves a typical dolichomacrostomid. The absence of an accessory glandular organ in the male gender warrants an assigment of Mactanea padinensis to the subfamily Bathymacrostominae Faubel, The monotypical subfamily Bathymacrostominae at present contains only Bathymacrostomum spirale Faubel, The female and male reproductive organs of Mactanea padinensis, however, deviate distinctly from Bathymacrostomum spirale. Mactanea padinensis is characterised by a single ovary and a complicated male stylet apparatus consisting of a main tube and up to four accessory stylets joined with the main tube at the proximal base. On the basis of these characters the new monotypical genus Mactanea is erected. Order Haplopharyngida Karling, 1974 Diagnosis. Platyhelminthes with pharynx simplex. Brain encapsulated, two ventral nerve cords. Ovary single, no accessory organs, female pore posterior to male one. Male copulatory apparatus with circle of sclerotised, straight stylets, some associated with prostatic organ. Feeliving, marine. Family Haplopharyngidae Karling, 1965 Diagnosis. Haplopharyngida with characteristics of the order. Type of the family: Haplopharynx Meixner, 1938 Genus Haplopharynx Meixner, 1938 Diagnosis. Haplopharyngidae with characteristics of the family. Type of the genus: Haplopharynx rostratus Meixner, 1938 Haplopharynx rostratus Meixner, 1938 (Plate XXIII: D-I; Figs ; Tabs 5,10) Type locality. Fehmarn, Kieler Bucht, BAL; leg. J. Meixner, 1930; types: deposition not recorded. Habitat. Eu- and sublittoral benthal (sand), down to 17m water depth, brackish and marine. Geogr. distribution. ANE: North Sea (North Frisian Islands: Sylt; Norway: Korsfjorden, Håkonsund, 2-3m water depth, Bondisholmen, 17m water depth; Scheldt estuary: Eastern Scheldt, Belgian coast), Skagerrak (Hållö, 4-10m water depth, Gullmarfjord), Celtic Sea (Isles of Scilly: St. Martin s flats, Modh s Ledge) (Faubel 1974, 1976, 1977a, Faubel & Warwick 2005, Karling 1965, Martens & Schockaert 1981, Schockaert et al.1989, Pawlak 1969). Morphological notes(plate XXIII: D-G). Body length up to 6.0mm (maximally extended), swimming thread-like, moving on sediment sluggish, resting often strongly contracted and adhesive to sand grains; anterior and posterior end with sensitive bristles; bristles of posterior end 20µm long; bristles of anterior end half as long as posterior ones. Whole body wall able to adhere to substratum; rear body often triangular when adhered. Epidermis ciliated allround, cellular with intra-epithelial nuclei; many epithelial cells with granular eosinophilous mucus 220

221 which will be stiffen thread-like when excreted to the exterior. Basal membrane thin. Body muscle wall faint and structured as usual. Anterior end with proboscis the opening of which overtopped by a small anterior lappet. The lappet is free of nuclei, glands and basal membrane but intensively innervated. Nervous system with subepidermal ventro-lateral nerve-stems. The proboscis, about 50-70µm long (m.f.s.), is walled by a thin membrane and provided with a complicate system of longitudinal pro- and retractores. The proboscis is crossed by glandular ducts, the glands of which lie ventro-laterally behind the pharynx; its secretion consists of needle-shaped rhammites. Pharynx simplex just behind brain. Pharyngeal glands extend into mouth opening from posterior. Intestine lesser ciliated than pharynx with Minotian cells and posterior anal-pore just dorsal of rear body-end. Reproductive system (Plate XXIII: H-I) with single testis and single ovary on the right side. Testis develops behind proboscis glands and ovary behind male copulatory apparatus. Growing up of oogonia directed posteriad; female gonopore posterior of last oocyte. Nothing more is known to the anatomy of the female apparatus. Male copulatory apparatus, about in mid-body, consists of seminal vesicle, prostatic vesicle, and distal stylet; next to the stylet lies the accessory prostatoid organ. Stylet and accessory prostatoid organ extend into antrum masculinum. Seminal and prostatic vesicle joined by an intervesicular duct; prostatic vesicle connected distally with straight stylet, 80-89µm long and distally cut obliquely. Accessory prostatoid organ with 8 (after Meixner 1938), 9 (after Pawlak 1969), and 7 (after Karling 1965) sclerotised rods arranged conically around a glandular bulb. Rods are bent distally inwards. Spermatozoa resemble all macrostomids in the lack of flagella and presence of bristle-like structures. During spermatogenesis, nuclei change from large irregular outline containing chromatine granules, to condense outline becoming round and finally elongate outline containing fibrillar chromatin. Immature sperm in testis are amoeboid, aflagellate, with numerous peripheral microtubules. Mature sperm have a nucleated part with narrow layer of cytoplasm drawn out into two flanges, and a thicker non-nucleated part; peripheral microtubules and dense thickenings of the plasma membrane are present in both parts. Two symmetrically arranged blunt bristle-like structures, apparently modified large granules not reaching the surface, are located in the nucleated part (Rohde & Faubel 1998). Ecological notes. Haplopharynx rostratus was sporadically found in sandy, detritus rich sediments of semi-exposed beaches in very low numbers (Pawlak 1969) (Fig. 78, Tab. 4). More intense investigations to the distribution was given by Scherer (1985). H. rostratus was regularly found in the halos of the tubes of Arenicola marina (L.) with numbers of up to 5 ind./10cm³ (Fig. 79). Juvenile individuals were found from December to March. The species undergoes a univoltine life cycle with sexual reproduction phase from July to October (Faubel unpub. data, Scherer 1985) (Tab. 10). Haplopharynx quadristimulus Ax, 1971 (Figs 9, 17C; Plate XXIII: J) Type locality. Canet Plage, France, Gulf of Lion, MED; leg. Sept. 1967; types: deposition not recorded. Habitat. Supralittoral stygal, on shore 5-6m from sea-water line, moist sand stratum of beach slope down to 40-60cm, marine. Specimens in association with Derocheilocaris remanei Delamare & Chappius. Geogr. distribution. ANW: USA (N Carolina: Bogue Banks, open ocean beach, Swansboro Coast Guard Station, beach on the inside of Bogue Banks (Rieger 1977). Morphological notes (only based on specimens in squashed preparation). Body length up to 5.0mm, thread-like. Whole body wall able to adhere to substratum. Anterior end with proboscis. Opposite to H. rostratus, the proboscis is entered by 8 10 glandular ducts, the 221

222 glands of which lie frontally, laterally and behind the pharynx. Pharynx simplex somewhat behind brain. Nothing was said to pharynx, gut and anal pore. Reproductive system (Plate XXIII: J) with single ovary. Testis (testes?) and entrance of vas deferens (vasa deferentia?) into seminal vesicle not determinable. Male and female organs follow close to each other in the second body-half. Male copulatory organ consists of main stylet, proximally funnel-shaped, distally pointed, and four sclerotised rods bent slightly inwards at distal tip; rods club-shaped proximally. Main stylet connected with prostatic vesicle; caudo-laterally of prostatic vesicle, evidently two seminal vesicles present. Ovary close behind male apparatus. Position of gonopore not given. Ultrastructural reconstruction of male copulatory system see Fig. 17C (after Doe 1986b). Remarks. Gerlach (1955) presented ecological data from a specimen determined taxonomically Haplopharynx sp. from the coastal groundwater table of sandy beaches of San Rossore, Tyrrhenian Sea. Later on, Fize (1963, p. 727, fig. 13f, f 1 ) described Haplopharynx sp. from sandy sediments, seawards to the Otoplana-zone, of the France Mediterranean coast, Le Grand Travers and Le Petit Travers, Gulf of Aigues-Mortes. The drawing given by Fize (1963) and the relatively neighboured localities found by Fize (1963) and Ax (1971), implicate that the species could be synonymous with Haplopharynx quadristimulus Ax, however, the description of Haplopharynx sp. is too scanty for a clear identification. Remarks. Haplopharynx quadristimulus (Carolina form) was collected by Rieger in July 1971 in 5 30cm sediment depth on beaches of Bogue Banks. As to the differences between the French form and Carolina form of Haplopharynx quadristimulus Rieger (1977) noted: There appear to be slight but significant differences between both forms, as well as between populations in N Carolina. However, there is no question that the N Carolina specimens are extremely similar morphologically to the French form of the species. Thus, both species (or groups of sibling species) of this genus appear to have an amphiatlantic distribution pattern and with this an extremely wide range of distribution of one very similar phenotype Haplopharynx sp. Tyler, 1976 (Fig. 5F) Localities. South shore, 1.5 miles from inlet, New River, North Carolina, USA, ANW; types unknown. Habitat. Sublittoral fringe, benthal, medium to fine sand, marine. Morphological notes were only given to the ultrastructure of the adhesive organ (Fig. F).. Ecological Account Sampling, Cultivation, Histology Macrostomida are small ( mm in length) and for the most part very fragile; they are easily damaged either when collecting or preserving. Freshwater species may be collected in small nets trawling through the water column or the phytal. A fine paint brush or a wide bore pipette can be effective to transfer worms from surfaces to a vial. For quantitative sampling of epibenthos associated with seaweeds, a plexiglass tube of appropriate diameter and height (depends on size of seeweed) may be used. Both openings should be able to plug with stoppers under water whereas the stopper on top of the tube should be provided with a tap for easier plugging and closing the tube under water. The species collections have to be sorted under a dissecting microscope. 222

223 Sediment sampling may be carried out with plexiglas core liner having a definite base area of 10 or 20cm² by a height of 5cm or if necessary more. Various methods of extracting are known; the best extraction process for macrostomids from sediment samples is achieved by the seawater-ice method after Uhlig 1964 (modified by Schmidt 1968 or Noldt & Wehrenberg 1984). Sexually mature specimens have to be studied alive and in squash preparation, i.e. flattened under the increasing pressure of the coverslip as the preparation dries. For histological observation, specimens have to be relaxed in 7% MgCl 2 and fixed in handwarm Bouin s fixative (15mL saturated aqueous picric acid, 5mL 36% formaldehyde solution, 1mL glacial acetic acid). Specimens longer than 1.0mm could be embedded in Paraplast plus (Reichert & Junk) or parafine, and smaller ones in Technovit 7100 (Haereus- Kulzer, Germany). Before embedding, specimens must be stained with eosin solved in 100% alcohol for greater ease of orientation in paraplast or plastic blocks and during sectioning. Specimens embedded in Technovit should be cut sagittally and transversally at µm, and specimens embedded in Paraplast should be cut at 4 6µm. Among other ones, staining with haematoxylin-eosin after Mayer (Romeis 1968) will present good results. Distribution, Abundance, Migration Apart from faunistic sampling surveys of diverse habitats or biotopes world-wide, studies on Turbellaria, especially Macrostomida, are hardly carried out, dealing with longer study periods in freshwater, brackish or marine biotopes. Disregarding studies with the so-called soft-bodied meiofauna founded herein because these animals must be studied alive and often determined with histological techniques. Longtime studies made by Den Hartog between 1960 and 1965 in the estuaries in the south-western part of The Netherlands, yielded 91 species of Turbellaria eleven of which were ranked among the taxon Macrostomida (Den Hartog 1977) (Tab 4). Bilio (1964, 1966, 1967) reported on longtime studies on the ecology of Turbellaria settling saltmarshes. In European saltmarshes five macrostomid species, ranked among tychocoenic species, were dominantly found (Bilio 1966). Tab. 4. Census of Macrostomida distributed in the estuaries of the south western part of The netherlands (after Den Hartog 1977). Total number of Turbellaria comes to 91 species. species habitat Archimacrostomum pusillum Macrostomum balticum Macrostomum distinguendum Macrostomum finnlandensis Macrostomum hamatum Macrostomum hystricinum Macrostomum rostratum Macrostomum spirale Macrostomum tenuicauda Microstomum lineare Microstomum sp. salt-marshes: eu-, poly-, mesohaline, intertidal flats of detritus-rich fine sand sandy mudflats, salt-marshes: eu-, poly-, mesohaline high littoral belt in freshwater tidal area high littoral belt in freshwater tidal area isolated brackish water ditches salt-marshes: eu-, poly-, mesohaline high littoral belt in freshwater tidal area salt-marshes, eulittoral sand- and mudflats: eu-, poly-, mesohaline, intertidal flats salt-marshes: oligo- and mesohaline freshwater tidal area, muddy creeks euhaline, intertidal sand flat 223

224 However, the only but very intensive autecological investigations were carried out yearround on the ecology of macrostomid species along coastal areas of the North Frisian Island Sylt, Germany (Pawlak 1969, Faubel 1974, 1976, Xylander & Reise 1984, Dittman & Reise 1985, Scherer 1985, Wehrenberg & Reise 1985, Armonies 1987 and Hellwig 1987, Armonies & Reise 2000). In the beginning of 2008, Ax published a very comprehensive investigation on the brackish water plathelminths of the northern hemisphere, distribution and taxonomy. After that census, the total of 342 Turbellaria, 40 Macrostomida, are documented by him. Data sets were achieved from saltmarshes and supralittoral, eulittoral and shallow sublittoral marine areas (Tab. 5). Main topics of these studies were investigations on abundance and population dynamics, vertical and horizontal distribution, tidal and seasonal migrations, and on life cycles. In the following, results of these investigations are presented in a short synopsis to document assemblage structures of Macrostomida in time and space which could generally mirror spacio-temperal patterning of environments and population dynamics of the group Tab. 5. Composition of species of Macrostomida and Haplopharyngida distributed in diverse biotopes of the North Frisian Island Sylt, Germany. Symbols denoting abundance, are indicated as following: - present but comment on abundance values absent, as = alien species, + regularly found, ++ dominant, +++ highly abundant. Abbreviations of biotopes: saltm = saltmarsh, hwb = high water belt of lentic areas, eusb = eulittoral sandy beach, eumf = eulittoral muddy flat, subs = sublittoral sands. Census assorted after Pawlak 1969, Faubel 1974, 1976, Reise 1984a, Xylander & Reise 1984, Dittmann & Reise 1985, Wehrenberg & Reise 1985, Armonies 1987, and Hellwig species saltm hwb eusb halo eumf subs Antromacrostomum armatum Archimacrostomum pusillum as +++ as + as Bradynectes sterreri as + - Frisiazona stylifera as Haplopharynx rostratus as + - Macrostomum balticum Macrostomum bicurvistyla as Macrostomum brevituba ++ Macrostomum curvituba Macrostomum hamatum ++ Macrostomum hystricinum as + Macrostomum minutum as + Macrostomum spirale +++ sp Macrostomum tenuicauda +++ Microstomum bioculatum Microstomum jenseni Microstomum papillosum as as ++ - Microstomum spiculifer ++ Myozona purpurea ++ Paromalstomum dubium as + + Paromalostomum fusculum Cylindromacrostomum notandum - Paromalostomum proceracauda as 224

225 In total, 23 macrostomid and haplopharyngid species (Tab. 5) could be determined from these areas of the North Frisian Island Sylt. Four species of the listing in Tab. 5, Macrostomum bicurvistyla, Frisiazona stylifera, Paromalostomum proceracauda, and Cylindromacrostomum notandum, could be sampled only sporadically and in very low numbers so that these species were only of interest for faunistic approaches. The habitats proper of these species are evidently elsewhere. The other species were regularly found and subject of intensive investigations over a longer period. Tab. 6. Proportion of species and abundance of Macrostomida in relation to total species and abundance of Turbellaria. habitat species abundance author hwl belt of lentic biotope 13 = 8.3% 12.4% Hellwig 1987 saltmarsh 7 = 9.3% Armonies 1987 Arenicola marina flat 3 = 3.6% 8.3% Reise 1984a, Scherer 1985 sand bar close to lwl 3 = 5.1% 0.2% Xylander & Reise 1984 sand hook close to lwl 3 = 4.6% 0.9% Xylander & Reise 1984 shallow sublittoral 6 = 6.5% % Wehrenberg & Reise 1985 estuaries: Scheldt, Rhine 11 = 12.1% Den Hartog 1977 European freshwater 51 = 7.3% Faubel & Norena 2004 Antromacrostomum armatum Myozona purpurea Paromalostomum fusculum mlwl Microstomum papillosum Microstomum spiculifer Archimacrostomum pusillum Frisiazona stylifera mhwl Bradynectes sterreri Haploph. rostratus Paromalostomum proceracauda Paromalostomum dubium Microstomum jenseni cgt sandy flat beach slope supralittoral 60 m 40 m 20 m 0 m 5 m 12 m Fig. 78. Horizontal distribution of Macrostomida and Haplopharyngida living in a semiexposed sandy habitat of the North Frisian Island Sylt, Germany (Faubel 1976). 225

226 Fig. 79. Vertical distribution of Parmalostomum fusculum, P. dubium, Bradynectes sterreri, and Haplopharynx rostratus in the vertical halos of oxic sediment of the tail shaft alongside burrow walls of benthic Arenicola marina L., performed August 1992 (Faubel unpublished). A single box corresponds a surface of 5cm² by a depth of 2cm. Abbreviations: o.l. = oxic sediment layer, a.l. = anoxic sediment layer. (pattern of Arenicola burrow after Reise 1985). The assignment of all the species found to distinct biotopes is given in Tab. 5. Superficially considered, the listing suggests that most of the species are evidently not restricted to distinct biotopes. They apparently offer a greater ecological valency. That impression will be greatly Paromalostomum fusculum hwl ind. (tot.): 535 June lwl cgt m 30m 20m 15m 10m 8m 6m 4m 2m 0m 1m 4m 7m 10m 12m sandy flat sand beach Fig. 80. Horizontal and vertical distribution of Paromalostomum fusculum. Each sample size of the first line from 50m flat to 1m sandy beach corresponds a surface of 10cm² by a depth of 2.5cm. All other samples correspond to a surface of 10cm² by a depth of 5.0cm abolished comparing more detailed the horizontal and vertical distribution of the species living on a semi-exposed sandy beach and flat as given in Figs Here, it becomes clear that most of the species - the exception being Paromalostomum fusculum (Figs 79, 80) demonstrating a wide ecological spectrum of valency; the same could hold for 226

227 mhwl Antromacrostomum armatum ind. (tot.): Myozona purpurea ind. (tot.): cgt: 104cm at 12.5m cm at 14m cgt m 1m 2m 3m 4m 5m 6m 7m 8m 9m 10m 11m 12.5m 14m sandy beach mlwl at 60m chcl m 9m 8m 7m 6m 5m 4m 3m 2m 1m 0m 1m sandy flat Fig. 81. Distribution of Antromacrostomum armatum and Myozona purpurea (figures italicised) on a semi-exposed sandy beach, May 1973 (after Faubel 1976). The sample size corresponds to a surface of 10cm² by a depth of 5.0cm (50cm³). 227

228 Archimacrostomum pusillum - settle only in distinct zones or habitats corresponding to their ecological niches. Examples are among others Bradynectes sterreri, Paromalostomum dubium, Haplopharynx rostratus, and Myozona purpurea. Bradynectes sterreri, Paromalostomum dubium and Haplopharynx rostratus were documented by Faubel (1974, 1976) and Pawlak (1969) as rare species with only sporadic occurrence. However, more intense investigations made by Reise (1984a), Scherer (1985), and Faubel (1992 unpubl.), proved that these species were dominantly found but distinctly restricted to the oxic halos alongside the walls of burrows of Arenicola marina (Fig. 79). Myozona purpurea is a deepliving form of sandy beaches where the coastal ground-water remains always oxic and sulfide is absolutely absent (Fig. 81). From this it is concluded that the distribution of species over diverse biotopes depends on the effective adaptation of the native ecological niche to the habitat where, based on the ecological valency, the species could develop and coexist in a community without displacingeach other. Macrostomida are generally living in marine and freshwater habitats of benthal, phytal, pelagial, and stygal zones providing the areas afford oxic conditions for survival and development. In non-oxic habitats, i.e. in sediment layers below the chemocline where sediment layers are of black colour and high concentrations of sulfide prevail, Macrostomida are absolutely non-existent. Though life of macrostomid species is only restricted to oxic habitats, some species are able to occupy specific local positions where the oxic gradient may decrease to lower values. These habitats correspond to deeper sediment layers just above the chemocline, e.g. Paromalostomum fusculum (Fig. 80), to the vertical halo of oxic sediment alongside of the tail shaft of burrow walls of benthic macrofauna, e.g. Bradynectes sterreri, Paromalostomum fusculum, P. dubium, Haplopharynx rostratus (Fig. 79), and to deeper zones of beach slopes above and within the coastal groundwater table, e.g. Myozona purpurea, Antromacrostomum armatum (Fig. 81), and in part Paromalostomum fusculum (Fig. 80). Macrostomum curvituba ind. (tot.): mid-littoral sea level cgt m 0.5m 0m 0.5m 1m 1.5m 2m 2.5m 3m 3.5m 4m sublittoral sandy beach slope Fig. 82. Distribution of Macrostomum curvituba of a subterranean coastal environment of a sandy beach in the Gulf of Finland (Ax & Ax 1970). The sample size correspond to 50cm³ sediment (10cm² surface/ 5cm depth). correspond to negative findings of specimens. 228

229 Species diversity and abundance of Macrostomida are generally very small (Tab. 5). As indicated in Tab. 6, the proportion of marine macrostomid to total turbellarian species varied between 3 species (3.6%) and 13 species (8.3%) depending on habitat. In this context it is of interest that the proportion of Macrostomida (51 species) to Turbellaria (674 species) known from European fresh-water systems (Faubel & Norena 2004), totals to a share of 7.3% of macrostomid species; that proportion ranks within the limits given above. Habitats composed of pure sand or sand mixed with mud, were more preferred than muddy flats; whereas semiexposed and lentic beaches proved a higher species diversity than exposed beaches. On a semi-exposed sandy beach 12 macrostomid species were encountered (Fig. 78) followed by a lentic beach of muddy sand (Hellwig 1987) and a salt-marsh with silty sediments (Armonies 1987) where 9 species were found, respectively. As to see in Tab. 4, lentic supralittoral areas of marine coasts being less often inundated and more influenced by rain, were settled to a greater degree with forms adapted to brackish water biotopes. Exemplary (Fig. 82), the subterranean distribution of the brackish water form Macrostomum curvituba should be cited, which was studied by Ax (1954) and Ax & Ax (1970) in the oligohaline area of the Gulf of Finland. The species is dominantly distributed in moisture sediment zones above and below the coastal groundwater level; but the species is also distributed in sublittoral sediments down to 5m depth of water (Luther 1960). A maximum value of abundance, 69 ind./50cm³, was Tab. 7. Fluctuation and proportion of abundance of Macrostomida in relation to Turbellaria living in an eulittoral semi-exposed sandy habitat of the island of Sylt (Sopott 1973, Faubel 1976). (Explanations: n = individual numbers, * = number of samples taken along a profile from lwl to hwl) months 1970 (Sopott 1972) III IV V VI VII *samples á 100cm³ Turbellaria (n) 2,083 3,623 3,263 4,270 4,444 Macrostomida 6.9% 9.2% 17.0% 13.2% 5.6% months 1973 (Faubel 1976) II IV VI VII X *samples á 100cm³ Turbellaria (n) 6,735 7,076 17,797 7,042 4,517 Macrostomida (n) proportion of Macrostomida to total Turbellaria 5.8% 9.3% 2.8% 3.2% 7.9% species of Paromalostomum (n) rest of Macrostomida (n) proportion of species of Paromalostomum to total Macrostomida 97% 94% 89% 92% 55% reported from the 2m-site of the beach slope (10-15 cm sediment depth) in August Hellwig (1987) reported on Macrostomum hystricinum distributed in supralittoral habitats, averaged 11.5 ind./10cm², though this species is only known from freshwater habitats. Possibly, this species could be identical with Macrostomum hystricinum marinum Rieger, The abundances of Macrostomida are generally very low mostly in the range of 1 to 13 specimens per 10cm² but the number of specimens could increase to a multiple at times of 229

230 high reproduction (Tab. 4). In Tab. 7 the abundance of Turbellaria and Macrostomida is listed from April to July for 1970 (Sopott 1973) and 1973 (Faubel 1976). Highest abundance values of Macrostomida occurred from April to June exactly to that time when the reproduction activity of most of the species occurred. That could also be followed up in Figs for the fluctuation of abundance of the species Myozona purpurea and Antromacrostomum armatum settling the zones of the coastal groundwater (Fig. 83), Archimacrostomum pusillum and Macrostomum balticum settling the hwl belt of lentic biotopes (Fig. 84), and Paromalostomum fusculum and Microstomum jenseni sandy flats (Fig. 85). The two maximum values of M. jenseni were based on vegetative (by paratomy) and sexual reproduction activity in spring and fall whereas the sexual reproduction occurred only in spring ind./100cm² I II IV V VI VII VIII IX X XI XII 1973 Myozona purpurea Antromacrostomum armatum Fig. 83. Fluctuation of abundance of Myozona purpurea and Antromacrostomum armatum on a semi-exposed sandy beach (after Faubel 1976). In March, 1973, samples were not taken ind./10cm² VI VII VIII IX X XI XII I II III IV V VII M. balticum A. pusillum Fig. 84. Fluctuation of abundance of Macrostomum balticum (muddy habitat grown with Spartina anglica Schreb.) and Archimacrostomum pusillum living in a lentic high water belt of a sandy slope (data from Hellwig 1987). 230

231 In eulittoral and supralittoral areas, populations settle distinct horizontal zones (Fig. 78). Depending on physical and climatic conditions and the ecological niches of populations, these horrizonzal zones could be restricted either to a very small belt or to a very wide area, cf. Paromalostomum fusculum (Figs 78, 80), and Myozona purpurea (Figs 78, 81). Extreme changes of abiotic factors, e.g. temperature, salinity, evaporation, could result in seasonal withdrawing into deeper sediment layers of the transition zone, flat/beach slope, where the chemocline is generally absent. In eulittoral sandy or sandy mud flats, the chemocline often prevents the individuals from evading into deeper sediment layers. Within the Macrostomida, seasonal changes were documented only for Paromalostomum fusculum by Pawlak (1969). Fig. 86 presents the vertical distribution of Paromalostomum fusculum in the transition zone around the 0m-site ( Strandknick ). The solid line expresses terms of the median depth above or below 50% of the population were sampled on the respective date. Dominantly, P. fusculum settled sediment layers between 2-4cm depth. Only in July, 50% of the population was sampled in the above 0-2cm sediment depth. In fall and winter (from Nov. to March) more than 60% of the population was migrated down to sediment layers deeper than 4cm. The deepest occurrence (24cm sediment depth, dotted line) was found in Februar ind./100 cm² IV V VI VII VIII IX X XI XII I II III Paromalostomum fusculum Microstomum jenseni Fig. 85. Fluctuation of abundance of Paromalostomum fusculum (data from Pawlak 1969) and of Microstomum jenseni (data from Faubel 1976) living in a semi-exposed sandy beach. Generally, sampling was performed by the investigators always at the time of low water and, therefore, the results reported, mirror the distribution of species always at low water. Therefore, Meineke and Westheide (1979) traced the question if tidal rhythms influence differences in the distribution of meiobenthos living in a sandy beach slope. The results yielded, were different (Fig. 87). Tide-depending horizontal and/or vertical migrators could be observed for most of the species investigated. The general trend is valid, the further the distance of the zone of settlement related to the "Strandknick" (0m site), the greater vertical distances were moved and horizontal migrations decreased. Vertical distribution offered a close correlation with the relative content of pore water (Meineke & Westheide 1979). Paromalostomum fusculum displayed a behaviour of vertical migration with varying 231

232 IV V VI VII VIII IX X XI XII I II III median depth 25 maximum depth sediment depth (cm) Fig. 86. Paromalostomum fusculum. Graph showing the seasonal distribution down to median (50%) and maximum depth of a semi-exposed sandy beach (values taken over from Pawlak 1969). Fig. 87. Paromalostomum fusculum. Vertical change of distribution in a beach slope depending on tidal level (after Meineke & Westheide 1979). A. Vertical change at low and high water at 4.5m-site. Temperature ( C) and content of pore water (%) related to sediment depth, were given at lw. Thin vertical line corresponds to sediment column sampled. B. Vertical migration of P. fusculum depending on incoming water. 232

233 Fig. 88. Migration behaviour of Microstomum papillosum and Microstomum spiculifer depending on life cycle. intenseness and differing directions (Fig. 87). The mean migration distancy amounted to 15cm between low and highwater. Meineke & Westheide reported that, in total, P. fusculum migrated nine times upwards and three times downwards at high water. The same behaviour of low intense tide-depending vertical migration was observed by Myozona purpurea and Antromacrostomum armatum. Another phenomenon of migration behaviour became evident analysing the population dynamics of Microstomum papillosum and M. spiculifer (Faubel unpublished data; Fig. 88). Both the species settle the lower beach slope but at different times within a year. M. papillosum was found there only in spring and early summer and M. spiculifer only in late summer and fall. All specimens were exclusively adult. Individual zooids were sexually mature and chains of zooids developed asexually by paratomy. Only at the beginning of each of the reproduction period (March / August), a few individual chains of zooids were observed in samples taking from the sandy flat. From that observations it was concluded that both the species offer a seasonal migration behaviour depending on the life cycle of each the species (Fig. 88). The lower beach, the breeding site, is that region of the beach where reproduction and spawning takes place. Eggs laid down in the interstitium, are drifting seawards with the run off of seawater rinsing out of the beach slope during ebbing. In a return migration specimens hatched in sublittoral areas, occupy again the breeding site for reproduction. Boaden (1968) reported that downward migration of Paromalostomum dubium (de Beauchamp) and much of the benthic fauna follows in response to vibration when sand is disturbed by the turbulence in the overlying water. Thus it seems that the majority of the interstitial species were able to avoid displacement from the substrate (Boaden 1968). Benthic turbellarians are not generally restricted to life in the sediment. Recolonisation, emigration or emergence from sediment occurs consistently and is often influenced by physical factors like light exposure, temperature, oxygen deficiency, decrease or increase in salinities, or life-style changes from entirely benthic to semi-planktonic (Reise 1984b, 233

234 Armonies 1988b, 1989). Increasing emigration of turbellarians from sediment in a gradient of light could be followed if light decreases. Mostly the species are pigmented. Archimacrostomum pusillum less pigmented, entered the water column at low photon flux density of 1µE m -2 s -1 (Microeinstein) (Armonies 1988b). Reise (1984b) investigated the recolonisation of Turbellaria in field experiments. Patches of 0.25cm 2 sediment were regularly made anoxic by raking the upper sediment layers down to 2cm sediment depth. That procedure caused all species to emigrate, in particular the diatomfeeding Plathelminthes such as Archimacrostomum pusillum. Plathelminthes recolonised quickly. Background densities were temporarily surpassed, first by predators, then by diatom feeders. Archimacrostomum pusillum was significantly less abundant after raking. Turning sediment to a depth of 5cm upside down decreased the abundance significantly. Diatomfeeders were most reluctant to recolonise because they attained control density between the 9 th and 20 th low tide period. Most obviously, Archimacrostomum pusillum exceeded the background density at the 37 th low tide period. Generally, sediment disturbances influences the pattern of abundances but not the species composition. Biomass The determination and evaluation of biomass weight for meiofaunal taxa are very laborious and, consequently, different procedures have been employed (cf. Faubel 1982). Determination of wet weight based on the formula presented by Andrassy (1956), is only practical for cylindrical and smooth organisms. Another appropriate biomass determination of worms warrants weighing filter dried batches with a microbalance which is more uniform and reproducible as well and promise a rather high reliability. Average dry mass weights (µg/ind.) of Turbellaria according to weighing of individuals of definite size classes are given in Tab. 8 (Faubel 1982). Tab. 8. Average dry mass weight (µg/ind.) of Turbellaria according to definite size classes (data after Faubel 1982). size classes mm mm mm Turbellaria 0.63 ± ± ± 1.67 Tab. 9. Biomass values of Macrostomida and total Turbellaria in salt marshes of the island of Sylt (data after Armonies 1986). ww = wet weight, dw = dry weight, afdw = ash-free dry weight (mg 10cm - ² = g m -2 ). ungrazed Puccinellion sheep-grazed Puccinellion sheep-grazed Armerietum Taxon ww dw afdw ww dw afdw ww dw afdw Macrostomida < Turbellaria

235 Armonies (1986) calculated dry weight and ash-free dry weight of Macrostomida living in salt-marshes (Tab. 9), on the assumption of an average density of ρ = 1.1g cm -3, the transformation of the sum of body volumes to wet weights, the assumption that dry weight is about 15% of wet weight (Ankar & Emgren 1976) and that ash-free dry weight is about 78% of dry weight (Widbom (1984). Reproduction, Life Cycles Sekera (1906) proposed the hypothesis that parthogenesis or self-fertilisaton is common among turbellarians (see Rieger et al 1991). Cultivation of Macrostomum marinum proves that embryos isolated in culture, become sexually mature and produce fertile eggs (Rieger et al. 1991, p. 92). After Ingole (1987) Macrostomum orthostylum produces subitaneous and resting eggs (Dauereier) in the salinity range between 0 and 21 thoughthe optimum rate for massculture ranges from 8 to 10 (cf. chapter Tolerance Experiments). Ax & Borkott (1969) portrayed the copulation and development of Macrostomum romanicum. Copulating, individual partners touch ventrally to one another directly opposed so that the male gonopore comes in close contact with the female gonopore of the partner. In that way, the hind ends of the bodies are mutually anchored by plunging the stylets into the vagina of the partner. Cross or uni-directional fertilisation occurs during anchorage. Within the Macrostomida, asexual reproduction follows the type of paratomy. Architomy as reproduction form is not known. Members of the Microstomidae and Myomacromum, Macrostomidae, have dominantly asexual and sexual life cycles. Tab. 10. Life cycles of Macrostomida. Abbreviations: g.t. = generation time per year, gen. = generations per year, l.c. = type of life cycle, s.r.p. = sexual reproduction period, u = univoltine, b = bivoltine, p = polyvoltine. (Data after Faubel 1976 and unpubl. data, Scherer 1985, Heitkamp 1982, Armonies 1987, Hellwig 1987) Species l.c. g.t.(gen.) s.r.p. Antromacrostomum armatum u 1 Febr. to July Archimacrostomum pusillum p <1 year-round Bradynectes sterreri u 1? May to Sept. Haplopharynx rostratus u 1 July. to Oct. Macrostomum balticum b (p?) <1 year-round Macrostomum brevituba u 1 year-round Macrostomum curvituba u 1 Febr. to May Macrostomum distinguendum p <1(1-5) April to Oct. Macrostomum finnlandensis p <1(2-3) June to Sept. Macrostomum hamatum u 1 Sept. to April Macrostomum obtusum b <1 April, Oct. Macrostomum orthostylum u 1 July Macrostomum rostratum p <1(1-5) March to Oct. Macrostomum spirale u 1 March to Oct. Macrostomum tenuicauda u 1 April to Oct. Microstomum jenseni u 1 May Microstomum lineare u 1 Oct. to Dec. Microstomum papillosum u 1 May to July Microstomum spiculifer u 1 August to Oct. Myozona purpurea u 1 April to July Paromalostomum fusculum u 1 March to May 235

236 Asexual reproduction is argued in the literature (Ax & Schulz 1959) that this form of reproduction has been arisen parallel several times within the Turbellaria. Rieger (1986) challenged this theory because of the discovery of Myomacrostomum unichaeta and M. bichaeta having sexual and asexual life cycles. The stem group of the Plathelminthes is hermaphroditic and reproduces sexually and asexually; the commonly accepted assumption of a hermaphrodite lacking asexual reproduction, is not warranted. Rieger indirectly confirmed the hypothesis of Jaegersten (1972) that the turbellarian archetype develop sexually, having a planctotrophic larva. Investigations on the embryology and postembryology performed on species living in marine semi-exposed beaches of the Island of Sylt (Faubel 1976), revealed that all developmental processes depend strongly on the temperature regime and supply of food (Apelt 1969, Faubel 1976). In cultivation experiments depending on different temperatures, intervals of temperatures could be determined in which the rate of development reached maximum values. The development of macrostomids is direct. Larval stages are unknown. Progenies commonly hatch after 2-3 days if the temperatures remain constant between 14 to 18 C for some time. Pawlak (1969) ascertained for Paromalostomum fusculum and P. dubium that the time of development needed 7 days from laying egg to hatching at C. The common size of hatched offsprings ranges between 250 and 300µm length of body. The length of time of postembryogenesis until animals becoming sexually mature is different, depending on the type of life cycle. There are life cycles with and without periods of dormancy. Life cycles with dormancy have developed Microstomum spiculifer, M. papillosum and M. jenseni. Individuals with univoltine life cycles become sexually mature after a complete year, individuals with bi- or polyvoltine life cycles, e.g. Macrostomum balticum, Archimacrostomum pusillum (Tab. 10), take a shorter course. Fig. 88. Life cycle of Microstomum lineare settling a freshwater pond near Bursfelde, Germany, (after Heitkamp 1982). White area = fraction of individuals undergoing vegetative phase of reproduction, grey area = fraction of individuals being in male maturity, black area = fraction of individuals developing resting eggs. 236

237 The development of progenies reaching sexual maturity, proceeds for most of the macrostomid species, undergoing a univoltine cycle, from April to July (Tab. 10) but also the extension of the reproduction phase to months of fall is often to observe. Only one species, Macrostomum hamatum, was documented by Armonies (1987) undergoing sexual maturity from Sept. to April during fall and winter. In Figs 90 and 91, the life cycles of Myozona purpurea, Antromacrostomum armatum, Microstomum papillosum, and M. spiculifer are itemised into stages of development for 1973 (Faubel 1976). The life cycles of Myozona purpurea and Antromacrostomum armatum underwent stages of development at congruent times per year (Fig.91). Different periods of development were assessed for Microstomum papillosum and M. spiculifer. M. papillosum developes in spring and early summer and M. spiculifer underwent the reproduction period in late summer and fall (Fig. 90). Sexual and asexual reproduction took place during the same time. Development of offsprings could not be assessed. In contrast offprings of Myozona purpurea and Antromacrostomum armatum developed immediately after the reproduction period. During fall and winter they grew up to maximum body length and became sexually mature in spring of the following year (Fig. 90). % 100 Microstomum papillosum Microstomum spiculifer 80 V A S 20 I II IV V VI VII VIII IX X XI XII 1973 a Fig. 90. Univoltine life cycles of Microstomum papillosum and Microstomum spiculifer. Abbreviations: A = individual zooids being sexually mature, S = senile individual zooids, V = asexually chaining zooids, n (M.p.) = total individual number of Microstomum papillosum, n (M.s.) = total individual number of Microstomum spiculifer. 237

238 J 1 60 % 100 Antromacrostomum armatum 80 Myozona purpurea J A S I II IV V VI VII VIII IX X XI XII n (My.p.) n (An.a.) Fig. 91. Univoltine life cycle of Antromacrostomum armatum and Myozona purpurea. Abbreviations: A = sexually mature specimens, J 1 = offsprings smaller than 300µm, J 2 = juveniles greater than 300µm, n (My.p.) = total individual number of Myozona purpurea, n (An.a.) = total individual number of Antromacrostomum armatum, S = senile individuals. 238

239 Freshwater species must have developed an adaptation capability to survive unfavourable environmental conditions in their habitats. Therefore, an important requirement of existence of turbellarians is the adaptation of its life cycle to the course of the year. That is indispensable for those species which settle periodical, i.e. temporary or seasonal, pools (Heitkamp 1988). Microstomum lineare and species of the genus Macrostomum (Tab. 10) are examples of eurythermal organisms which extend their life cycles over the period of vegetation growth from March/April to October/November (Bauchhenss 1971, Heitkamp 1982, Rixen 1961). Tolerance Experiments Generally, it is known that species prefer to settle habitats controlled by distinct ranges of salinity and temperature whereas the range preferred, is smaller than the range which could be tolerated (Armonies 1986). Laboratory experiments on the salinity preference of Paromalostomum fusculum performed in an artifial system provided with both combusted sand and undisturbed sand from the habitat, revealed that Paromalostomum fusculum tolerated salinities from 6 to 38 (Faubel unpubl. data). After 24h more than 63% of specimens were accounted for within the salinity range between 23 to 32. The range from freshwater to 6 salinity and from sediments with salinities higher than 34 were free of specimens. About 12.5% of the specimens introduced in the experiment could not be refound. Macrostomum orthostylum (Braun) was collected from a brackish water fish-farm at Kakinada (A.P.), India, and cultivated succesfully over several decades (Shirgur 1980, Ingole 1997). Tests of the range of salinity tolerances (1-34 ) of M. orthostylum revealed (Fig. 92) that specimens could survive in salinities between 0 and 30 (Fig., Ingole 1988, permission for reproduction was not given). Under controlled environmental conditions, maximum survival of 112 days was found in a salinity range around 9. In higher salinites survival of specimens decreased rapidly. Within a range of 22-26, 50% of the specimens were died after 5 days and the remaining specimens (50%) died within the next 18 days (Fig. 92). Fig. 92. Salinity tolerance experiments in Macrostomum orthostylum, with 25%, 50%, and 100% mortality, and correlation of maturation (95% confidence limit) with salinity (after Ingole 1988). 239

240 Maximum growth rate (0.99mm length of body) was attained in 56 days with an average growth rate of 15.7µm per day in optimum salinity around 9. Sexual maturity was attained after 7-12 days after hatching in salinities between 1 and 11. Reproduction proceeded in salinities from 0 to 22 (Ingole 1988, 1997). I must desist from reproduction of Fig. 2, Ingole 1987, in this context because Interscience Wiley (UK) did not grant permission to use Fig. 2 without charge. Fig. 93. Relationship between hatching rate and temperature in dormant eggs of Macrostomum orthostylum (Braun) (Ingole 1987). Bělehrádek s equation after McLaren (1966); D = days, T = temperature, a = difference in mean slope, α = shifts on temperature scale, b = degree of curvilinearity of the response quite adequately over the vital temperature range. Fig. 94. Diagrams indicating the path of specimens of Microstomum caudatum placed in freshwater when encountered a drop of 0.05% salt solution (s) (A. C) or placed in 0.05% salt solution encountering a drop of freshwater (f) (D-F). (after Kepner & Taliaferro 1912). Hatching from eggs was observed over a wide range of temperatures. Greatest hatching rates occurred at C and poorest at C (Fig. 93). Individuals cultured at salinities of and a constant temperature of 24 C (Figs 1-2, Ingole 1987), produced both subitaneous and dormant (resting) eggs. Hatchlings from subitaneous eggs were observed after 48 hours. Dormant eggs desiccated for 30 days, were hatched after 25 days at 24 C and a salinity of 9. Individuals cultured at salinities of 7-11, produced 94 eggs as a maximum within a life span. Single reared specimens produced only subitaneous eggs within the salinity range from 1 to 21 at intervals of 3-4 days. In cultures with two specimens, subitaneous and dormant eggs were produced in the same salinity range. However, the highest production of eggs occurred in salinities from 7 to 11. The reduction of egg production of both types of eggs started after 75 days (Ingole 1987). Testing the physiological function of the ciliated pits and pharynx, Kepner & Taliaferro (1912) performed experiments to see the response of M. caudatum when they get in contact with water of low concentration of salt (0.05% and 0.1% acetic acid solution). Concentrations of higher than 1/25% acetic acid solution.were dangerous or fatal media to the species. Under normal conditions, it was observed that specimens make numerous exploratory movements as 240

241 they swim by thrusting their anterior ends to and fro, thus testing the water by means of their cialited pits and anterior pharynx. If specimens came in contact with salt conditions of 0.5% (a drop saltwater was placed on the slide surrounded by freshwater) they reacted promptly by turning away from the salt solutions (Fig. 94A-C). If a drop of freshwater was surrounded by a low solution of saltwater and specimens were placed into the saltwater solution then specimens moved into the freshwater drop if coming in contact with the drop. Specimens entered the freshwater drop, were caught in the drop and did not leave the freshwater (Fig. 94 D-F). Geographic Distribution Macrostomida are ubiquitously distributed in freshwater, brackish or estuarine waters, and marine environments. They are living dominantly on muddy and on/in sandy sediments, on plants and seeweeds; they are less dominant in plankton. In beaches the habitat could extent down to the coastal groundwater table. To date species are not documented to associate with other organisms in symbiotic or ectocommensal partnership and, least of all, in parasitic lifeform. In benthic systems macrostomids are generally represented in oxygenated sediments; they also occur in the halo of oxic sand around burrows of macro-endofauna. The chemocline of sediments, if present, is a distinct boundary for life in deeper sediments. References An Der Lan, H., 1939: Zur rhabdocoelen Turbellarienfauna des Ochrid-Sees (Balkan). Sber. Akad. wiss. Math.-Nat. Kl. Wien, Abt. I. 148: An Der Lan, H., 1961: Zur Ökologie und Populationsdynamik rhabdocoeler Turbellarien im Ohrid-See. Arhiv Biol. Nauka - Archs Sci. Biol. (Beograd) 13: An Der Lan, H., 1962: Zur Turbellarienfauna der Donau. Arch. Hydrobiol.(Suppl.) 27: An Der Lan, H., 1967: Zur Turbellarien-Fauna des hyporheischen Interstitials. Arch. Hydrobiol. Suppl. 33: Andrassy, J., 1956: Die Rauminhalts- und Gewichtsbestimmung der Fadenwürmer (Nematoden). Acta Zool. Budapest 2: Ankar, S., Elmgren, R., 1976: The benthic macro- and meiofauna of the Askö-Landsort area (Northern Baltic Proper). A stratified random sampling survey. Contrib. Askö Lab. 11: Antonius, A., 1968: Faunistische Studien am Roten Meer im Winter 1961/62, Teil IV. Neue Convolutidae und eine Bearbeitung des Verwandtschaftskreises Convoluta (Turbellaria, Acoela). Zool. Jb. Syst. 95: Apelt, G., 1969: Fortpflanzungsbiologie, Entwicklungszyklen und vergleichende Frühentwicklung acoeler Turbellaria. Mar. Biol. 4: Armonies, W., 1986: Free-living Plathelminthes in sheep-grazed and ungrazed supralittoral salt marshes of the North Sea: Abundance, biomass, and their significance in food chains. Neth. J. Sea Res. 20: Armonies, W., 1987: Freilebende Plathelminthen in supralitoralen Salzwiesen der Nordsee: Ökologie einer borealen Brackwasser-Lebensgemeinschaft. Microfauna Marina 3: Armonies, W., 1988a: Common pattern of Plathelminth distribution in North Sea salt marshes and in the Baltic Sea Arch. Hydrobiol. 111: Armonies, W., 1988b: Physical factors influencing active emergence of meiofauna from boreal intertidal sediment. Mar. Ecol. Prog. Ser. 49:

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265 Appendix Abbreviations of locations of holo- and paratypes and voucher specimens deposited AMNH-N Y American Museum of Natural History, New York AM-S Australian Museum, Sydney BGFEASU-C Biological and Geological Faculty of Education, Ain Shams University, Cairo, Egypt BMNH-L British Museum (Natural History), London BOC-NH Bingham Oceanographic Collection of Yale University, New Haven, Connecticut, USA. DZASU-C Dept. of Zoology, Ain Shams University, Cairo, Egypt DZSLU-SP Department of Zoology, Sciences and Letters of the University of São Paulo, São Paulo MNHN-P Muséum National d Histoire Naturelle, Paris MLP-BA Museo de La Plata, Buenos Aires, Argentina NMNHSI-W National Museum of National History, Smithsonian Institution,Washington D.C. NHM-W Naturhistorisches Museum Wien NMNS-O National Museum of Natural Sciences, Ottawa NHR-S Natur Historika Riksmuseet, Stockholm NSM-T National Science Museum, Tokio QM-B Queensland Museum, Brisbane RISU-CH Reseach Institute of Shenzhen University, China SAM-A South Australian Museum, Adelaide SM-F Senckenberg Museum, Frankfurt USNM-W United States National Museum, Washington, DC ZI-StP Zoologisches Institut, St. Petersburg ZIM-H Zoologisches Institut und Museum, Hamburg ZMU-G Zoologisches Museum der Universität, Göttingen Abbreviations of zoogeographic regions (following Wallace' Zoographical Regions) EUROPE European subregion (incl. northern mediterranean subregion) ETR Ethiopian Region AUS Australian Region EPA East Palaearctic Region (Siberian and Manchurian subregions) NAF North Africa incl. Sinai (southern part of mediterranean subregion) NEA Nearctic Region NEO Neotropic Region NRE Near East Region (eastern part of mediterranean subregion) ORR Oriental Region Abbreviations of subregions of European Russia (cf. Fig. 99) RU-C Russia central RU-E Russia east RU-KGD Russia, Kaliningrad section (Russian part of East Prussia) RU-N Russia north RU-S Russia south RU-W Russia northwest 265

266 Abbreviations in text, figures, and tables alt. altitude above sea level cgt coastal ground water table chcl chemocline EM electron microscopical halo oxic sediment alongside the walls of macro-endofauna burrows hw high water (m)hwl (mean) high water level i.l. incident light l.b. lower beach lw low water (m)lwl (mean) low water level Md Median of grain size m.f.s. m.l.s. mtl n POM QDI s.h. SkI T t.l. u.b. measurements taken from fixed specimens or serial sections measurements taken from living specimens mid-tide level individual numbers Particulate Organic Matter Quartile Deviation Index spring horizon Skewness Index temperature transmitted light upper beach Abbreviations in morphological and anatomical Figures acg accessory gland acs accessory stylet / spine ad adhesive glands ae abortive eggs af atrium femininum ag atrium genitale anc anchor cell ast attached sperm-tube au auricula ax axon b brain bb basal body bbp blastema of brain-pharynx predisposition bc bulb cell of cso bd developing brain bgp blastema of genital predisposition bl basal lamina bm basement membrane bo bursal organ bp basophilic plasma bpa bp of animal pole bpe bp of equatorial region bs seminal bursa bsc bursal canal bw body wall bwm body wall muscles c cowl or hood ca cilium(-a) cb cirrus bulb cc canal cell cch ciliated chamber ccr ciliated crypt ccs canal cell of cso cde cell of de ce centriole ceg cephalic glands cf circular muscle fibres cfr circular fibriles cg cement glands cga connective ganglia cgo common genital pore ci cirrus cla closure apparatus cn nematocyst co caudal organ coc connecting cell com commissure cp caudal plate cpc cup-shaped pigment cell cpg cyanophilous prostatic glands cro ciliary rootlet cs contact substance cso caudal sensory organ csp ciliary sensory pit cte cell type of epithelium cyc central yolk cell d diatoms dcg ducts of cephalic glands de ejaculatory duct dfr diagonal fibriles dgi ductus genito-intestinalis dm dilator muscle dr distal rod 266

267 ds spermatical duct dsp spermatic duct dv vaginal duct dz division zone e eyes ebc epithelial blastema cells ec end cell ecm extracellular matrix ed epidermis egc enzymatic gland cell ep excretory pore eop eosinophilous prostatic glands epg extravesicular prostatic glands ept epitheliosome er endoplasmatic reticulum erw external ribs of weir es excretory system esg egg-shell globules eso esophagus est extracellular stroma f food fe feces fp female gonopore fvs false seminal vesicle g glands ga genital apparatus gb genital blastema gcc granular club cell gd glandular duct of epg gg glycogen granules go genital opening goa Golgi apparatus gp girdle of pigment gr granules gst glandular stylet gt glandular tube hc hull cells hm hull membrane i intestine icm intercellular matrix il internal leptotrich irw internal ribs of weir ivd intervesicular duct la lamella lf longitudinal muscle fibres lfr longitudinal fibriles ln lateral nerve lnf longitudinal nerve fibre lo lobe m mouth ma male atrium mao male accessory organ mc Minotian cells mcb male copulatory bulb mco male copulatory organ med medulla mes mesenchyme mf muscle fibres mi microtubule mip mid-piece mit mitochondrium mop mouth-piece mp male gonopore mrg muscle ring on gut ms matrix syncytium mv microvilli n nerve na anterior nerve cord nc nerve cell nd dorsal nerve cord nf nerve fibre ncs nerve of cso neu neuron nm main nerve cord nnp peripheral nerve net nni intestinal nerve net np neuronal process nsw nerve swelling nu nucleus nv ventral nerve cord o opening ooc oocyte oog oogonium ov ovary ovd oviduct p pigment pa prostatic ampulla pb polar body pc pigment cell pd prostatic duct pdy presumptive dorsocentral yolk cells pg prostatic grains ph pharynx phc phagocytic cell phg pharyngeal glands phn pharyngeal nerve ring pg prostatic glands pog preoral gut pon post-oral commissure pr proboscis prs proboscis sheath pym presumptive yolk mantle 267

268 r retractor muscle rc receptor cell rg releasing gland rh rhabdite rm rhammites rmg rhammite glands rmt rhammite tracks rpv reduced prostatic vesicle rw ribs of weir s intracellular septa sbo sclerotised apparatus of bursal organ sco striated cortex scp sclerotised process se secretion sd sclerotised duct sgt stopper of gland tubes sh sclerotised horn sha sensory hairs sj septate junctions sm septum muscles so subterminal opening sp sperm sph spincter spi spine spt sperm-tube spv seminal prostatic vesicle st stylet stc stem cells sv sclerotised vesicle t testis tc terminal cell tca terminal capsule of cso tnf transverse nerve fibre tng tail nerve ganglion tp tunica propria tu tunica tw terminal web v vagina va vacuole vd vas deferens vg prostatic vesicle vig viscid gland vp vaginal gonopore vs seminal vesicle w weir y yolk ydc yolk depleted cells ym yolk mantle male gonopore female gonopore Indices from 1 up to 6 indicate different types of cells or directions of orientation. 268

269 Fig. 94. Delimitations of sea areas abutting to Eurasia, Greenland, Africa, Australia and Antarctica. Indices of sea areas used in the taxonomic part: ANE - Atlantic North East, AOE - Arctic Ocean East, ASE - Atlantic South East, ASW - Atlantic South West, BAL - Baltic Sea, incl. Kattegat, IO - Indian Ocean, MED - Mediterranean Sea incl. Black Sea, PCW - Pacific Central West, PNE - Pacific North East, PNW - Pacific North West, PSE - Pacific South East, PSW - Pacific South West, SOE - Southern Ocean East, SOW - Southern Ocean West. Fig. 95. Delimitations of sea areas abutting to America, Greenland and Antarctica. Indices of sea areas used in the taxonomic part: ANW - Atlantic North West, AOW - Arctic Ocean West (further ones see Fig. 94). 269

270 Fig. 96. Delimitations of sea areas of the North Sea and Baltic Sea. Abbreviations: Br.C. Bristol Channel; K. Kieler Bucht; M. Mecklemburger Bucht; N.C. North Channel; Sea Heb. Sea of Hebrides; south. N.S. southern North Sea; pt part. 270

271 Fig. 97. Delimitations of Sea areas of the Mediterranean Sea. Abbreviations: A. Sea of Asov; Al. Sea Alboran Sea; G.L. Gulf of Lion; G. Sidra Gulf of Sidra; G.T. Golfo di Taranto; Li. S. Ligurian Sea; M. Sea of Marmara; S. Cr. Sea of Crete; Ve. Gulf of Venice. Fig. 98. Delimitations of the Austral Asiatic Sea areas. Indices of sea region: AAS (Austral- Asiatic Sea). 271

272 Fig. 99. Oblasts of Russia and abutting nations. Index of nations after Top Level Domains by country Code (TLD Code). Oblasts of Russia: RU-C: Central European Russia; RU-E: East European Russia; RU-N: North European Russia; RU-S: South European Russia; RU-W: Northwest European Russia; RU-KGD: Kaliningrad region. 272