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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Eclipidrilus

Eclipidrilus Eisen, 1881 (ref. ID; 6564)

Family Lumbriculidae (ref. ID; 5939, 6422, 6564)

ref. ID; 1663

Setae single-pointed. Four bundles of two setae each per segment. Usually reddish or brownish worms. 20 to 50 mm long. In mud or debris of pools, ponds and lakes. One pair of male gonopores on X. Prostomium rounded or with a proboscis. Widely distributed. (ref. ID; 1663)

ref. ID; 1923

Spermathecal pores in segment 9; Prostomium rounded. Single species. (ref. ID; 1923)

ref. ID; 6564

Lumbriculid clitellates with male pore(s) in segment X, spermathecal pore(s) in IX, and atria elongate with spiral muscles. Spermathecae may be paired with ventrolateral pores, paired with median pores, or single and median. Atria may be paired, lost on one side although pore is present, or single and median. Penial structures variable. Testes paired in IX and X or only in X, male funnels small or absent in IX, large in X. Ovaries in XI, often extending posteriad, female funnels in 11/12. Setae single-pointed. Prostomium with or without a proboscis. (ref. ID; 6564)

Type species

Eclipidrilus frigidus Eisen, 1881 (ref. ID; 6564)
  1. Eclipidrilus asymmetricus (Smith, 1896) (ref. ID; 6564) reported author and year? (ref. ID; 5939)
  2. Eclipidrilus daneus Cook, 1966 (ref. ID; 6564) reported author and year? (ref. ID; 5939)
  3. Eclipidrilus fontanus Wassell, 1984 (ref. ID; 6564)
  4. Eclipidrilus frigidus Eisen, 1881 (ref. ID; 1923, 6554) reported author and year? (ref. ID; 5939)
  5. Eclipidrilus ithys Brinkhurst, 1998 (ref. ID; 6564 original paper)
  6. Eclipidrilus lacustris (Verrill, 1871) (ref. ID; 6564) reported author and year? (ref. ID; 5939)
  7. Eclipidrilus levanidovi Sokol'skaya, 1983
    See; Styloscolex levanidovi (ref. ID; 6564)
  8. Eclipidrilus palustris (Smith, 1900) (ref. ID; 6564) reported author and year? (ref. ID; 5939)

Eclipidrilus asymmetricus (Smith, 1896) (ref. ID; 6564) reported author and year? (ref. ID; 5939)

Descriptions

The USNM collection contains the paratype (USNM00024588), which is said to be post reproductive (Wassell 1984) and not of any great value (Cook 1966). The species differs from E. frigidus by the presence of a proboscis, a single median spermathecal pore and male pores, and a sigle atrium but paired spermathecae. It has not been collected in this century. Wassell (1984) searched Quiver Lake, Illinois, the type locality, but did not find it. According to the original description, the spermathecal pores are median, one in front of the other, and both spermathecae lie on one side. There is one pair of testes in X. The mall pore is in the midline at the posterior end of X. The male pore is in the midline at the posterior end of X. The male funnel (described in the singular) is at 10/11. The atrium proper lies in XII-XIV and is connected to the penis sac through a thin ejaculatory duct in XI. The original description then states: "Outside of the muscular layer is a layer of small, deeply-staining cells, which in some places are scattered. This layer is nowwhere more than one cell in thickness....Surrounding the reservoir, and connected with it, is a thick layer of tissue of a reticulate character, which is constricted by the septa." In the illustration (Smith 1896), the thicker layer looks somewhat like developing sperm in the sperm sac rather than prosate cells, but it could be prostate tissue. In Fig.8 the prostate layer is illustrated as thin. The penial sac (originally compared to the so-called prostate of E. frigidus) has a thick epithelial lining layer, in contrast to the atrium and ejaculatory duct. The description goes on "At a point just anterior to the septum X/XI is an enlargement of the duct and an expansion of the lumen to form a small chamber in which is a marked change in the lining epithelium, this layer becoming much thinner and the cells more scattered. The terminal portion of the duct extends from the chamber above referred to ventrad to the male pore. The structure of this portion of the duct leads me to believe that this worm has an eversible penis." The term eversible was used by Smith, although in his illustration the structure could be interpreted as a thin penis like that of Eclipidrilus palustris and E. daneus. Otherwise this description compares favorably with that of E. frigidus, except that the male duct is shorter. Also, the male pore is associated with gland cells not observed in E. frigidus. (ref. ID; 6564)

Eclipidrilus daneus Cook, 1966 (ref. ID; 6564) reported author and year? (ref. ID; 5939)

Descriptions

The longitudinal sections known to be paratypes lack anterior testes, as originally described. The atria are 130 µm wide and their muscle layers 30 µm thick, with a distinct epithelial lining 7.5 µm thick. The penis lie in curved penial sacs that originate close to the dorsal body wall and are associated with strong retractor muscles and a cluster of glands. In the other USNM material, the spermathecal ampulla may be reflected forward into VIII. The Bay St. Louis material closely matches the type series. The worms are 6-17 mm long and 0.5 mm broad. There are 20-77 segments. The proboscis is short. The spermathecae have thick muscular ducts in IX-X that open into a thin-walled duct-like section (? of the ampulla) in X or XI (in one specimen); in another example the thick- and thin-walled ducts are coiled in IX, and the beginning of the ampulla also lies in that segment. The narrow ectal part of the ampulla is followed by the ental ampulla, which may be 200 µm wide, with walls of thick vacuolated cells about 50 µm thick. The ampulla may extend posteriad to XIII. There are sperm stored in the thin-walled section. The spermathecal duct at the pore measures 60-90 µm, the epithelial layer is 20 µm thick, and there is a thin muscle layer. The actual pore forms a vestibule with a folded wall. The anterior male funnel is very small and there are no anterior testes. The atrium is 200 µm across, with a wall 70 µm thick. One of the vasa deferentia (in a disection) is 50 µm wide. The atrium extends posteriad as far as XVI, where the prostate glands are thick. The ejaculatory duct at its origin in XI is 50 µm wide, with muscular walls 15 µm thick and a distinct epithelial lining. This duct then narrows to return to the ental end of the penis in XIII, where it turns through 180 degrees to enter the penis. The penis is a complex structure. The penial sac extends up to the dorsal body wall in XIII. Attached to it are a large retractor muscle and brunches of gland cells. It curves anteriorly and ventrally, as in E. palustris. The sac may be up to 100 µm in width. The penis itself has an exceedingly thin outer layer with very flat nuclei, within which is a layer surrounding the lumen, the two layers again connected by thin fibers. The penis is only 20 µm across. At the male pore, the body wall forms the equivalent of a pendant penis in a small sac, but the thin true penis is extruded through the opening of this structure. When everted, the whiplike penes are longer than the body width, as indicated by the length of the penial sacs. When dissected, the sac and penis form a stiff structure; the penis may be folded but is not coiled. Material catalogued as USNM00026301 comes from Montana a source distant from all other records of E. daneus (South Carolina, Louisiana, Mississipi). This consists of sections (by J.E. Kindred, from F. Smith) numbered 0.487 (longitudinal) and 0.488 (transverse). The transverse sections conform to the description of E. daneus. The spermathecae extend only just beyond the male pore because they are coiled. The ental end has vacuolated cell walls 50 µm thick; the ampulla is 170 µm wide. Ectally the wall is thin and the spermathecal duct is 55 µm wide. The ental end of the atrium is ca. 100 µm across (wall 27.5 µm, muscle layer of wall 15 µm, lumen 40 µm). In the midregion it is 130 µm across (30, 25, and 70 µm, respectively) and ectally 125 µm (25, 20, and 75 µm respectively). The ejaculatory duct at the penis is 25-30 µm wide. The penis is coiled once within the penial sac (so that it appears three times in a single section). The penial sac is 85 µm wide entally (wall 5 µm and penis 70 µm, with a narrow lumen between the two). Ectally the penial sac narrows to 50 µm, with the penis 25-28 µm. Examination of the longitudinal sections initially suggested that a different taxon was involved because the penial sac does not have the semirigid curved form. Instead the penis is strongly coiled within a flaccid sac that is pinched to a narrow tube at the septa. This structure lies along the dorsal body wall, but is connected by a strand of poorly defined cells running anteriad and ventrally in the usual curved path. The strand ends at the body wall but no clearly defined male pore could be observed. There are a few sperm in the atria of this specimen, but the spermathecae are full of amorphous material. This may be regarded as a postreproductive specimen with a degenerating male duct. The male duct development was observed in some specimen from Louisiana. The LSU material conforms to the description of the type material except as noted below. In all instances, the penial sac is curved from the dorsal body wall toward the male pore. When dissected, it appears to be stiff and to largely retain its shape. In a dissected specimen the atrium is 2.3 mm long to the point where it narrows to form the ejaculatory duct. The penial sac is of a similar length. The atrial walls are 48 µm thick and the lumen 142 µm wide. The penial sac entally is 95 µm wide and the ejaculatory duct at the ental end is 30 µm wide. The spermathecal ampulla in a dissection is 520 µm across, the duct 85 µm wide. In one specimen with everted penes, the penial sac reaches back through XI to the beginning of XII rather than the usual XIII. This is presumably its contracted state, which will be opposed by the large ental retractor muscle. In specimen 3183 the coild penes are associated with a partially developed reproductive system and the spermathecae are a fingerlike mass of cells but a small lumen has developed entally. The atrium is not fully developed. The penial sac extends to the dorsal surface of XII with the penis twisted and coiled within it. The atrium extends only a little beyond the penial sac and has a lumen only at the ental end; the walls are closely appressed in the rest of the atrium. (ref. ID; 6564)

Remarks

Cook (1966) designated only slide series 0.138 as the paratype. He cited USNM00026300, material from Covington, La., and USNM00026357, New Orleans, La., as "other material." The latter still exists as a separate catalogue entry and consists of 5 specimens examined superficially in this study. The catalogue number 00026300 was no longer listed as such, but as 00032908, 47 slides and specimens in alcohol. These are all labeled paratype in the catalogue, although they were not so designated by Cook (1966) in print. The writing is not that of D.G. Cook. They have been recatalogued as 00026300. Material catalogued as LSU3181 consists of one whole mount with everted penes and a longitudinal section series on 4 slides plus the mounted tail. These specimens bear no resemblance to Eclipidrilus. There is no proboscis, the atria are short, the spermathecae are spherical with long thin ducts, and the penes when everted are thick and finger-shaped. This taxon will be described elsewhere. The slide numbered LSU3178 is a large animal, similar in overall dimensions to E. daneus, but it appears to have a short atrium in X connected directly to the male pore via an ejaculatory duct. A thin tip of a penis is visible. The spermatheca also seems to be short and restricted to IX. Both spermatheca and atrium are full of sperm. There is a notch on the end of the prostomium but no proboscis. This taxon cannot be identified for certain. Cook (1966) states that longitudinal muscles are involved in the penial sacs. As both the penial sacs and atria may be derived from inverted body wall, the muscle layers of both are likely to be continuous with the body-wall musculature. The penial structure is essentially the same as that described above for E. palustris, a species with a very thick atrial wall and narrow lumen. (ref. ID; 6564)

Type locality

Covington, La., from Lousiana Southern Biological Supply Company, 1 June 1916. (ref. ID; 6564)

Type materials

  • Holotype: USNM00032907, slide series 0-138a-e, transverse sections by J.E. Kindred, ca. 1916, F. Smith collection (? vial 0.138, not examined, probably tail of specimen), split from USNM00026300. (ref. ID; 6564)
  • Paratype: USNM00032908, slide series 0.139a-b, longitudinal sections as above (? vial 0.139, presumably tail end), split from USNM 00026300, regarded as sole paratype. Some of the "other material" has been labeled as paratype at some time by the USNM, but was not so designated by Cook. It is not currently catalogued as paratype material. (ref. ID; 6564)
  • Other material:

    Eclipidrilus fontanus Wassell, 1984 (ref. ID; 6564)

    Descriptions

    The spermathecal ampullae are small and limited to IX. There is no thin-walled section of the ampulla. The pores are surrounded by large, lobed glands. The spermathecal ducts are muscular with an epithelial lining, one duct being 30 µm wide. The atria may extend posteriad as far as XIII. The prostate layer is thin, being thickest entally. The atrial muscular layer is 35 µm thick in one specimen and the lumen 85 µm wide but varying with the degree of compression. The male ducts emerge through thick (?glandular) pads. The ejaculatory ducts are 25-28 µm wide, with muscular walls and a lining epithelium. The duct is erect in X, but may be coiled entally. The penis is a small, papilla-like structure. There are testes in IX in one specimen, but no sperm on the small funnel, although there are sperm in the spermathecae and atria and on the larger male funnels in X. The ovaries are long, reaching to XIII. Sperm sacs were observed in various segments from XI to XV, but no anterior sperm sac was oberved. Egg sacs observed any where between XII and XIX, usually occupying 3 or 4 segments. (ref. ID; 6564)

    Remarks

    Wassell (1984) described the essential features of this species, but failed to note the glandular structures around the male and spermathecal pores. This was despite mentioning the glandular male pores of E. palustris. He stated that penes were present, consisting of protrusible extensions of the distal duct of the atrium (= ejaculatory duct) without cuticularization. In the whole-mounted specimen examined, a surface view of the male pores shows a very small opening in a circular structure, surrounded by a doughnut-shaped ring of tissue. In section, these can be seen as the papilla-like end of the male duct and the ring of glandular tissue, respectively. It seems better to avoid the term penis for this simple structure. The spermathecal duct has the usual muscle and epithelial layers, and the current measurement is close to that quoted by Wassell (30 µm versus 25 µm, but the duct can be ovoid in sections), but he stated that there was no muscular thickening. In one of the sections examined, the ejaculatory duct appears erect in X. The sectioned material has faded and is difficult to photograph. (ref. ID; 6564)

    Type materials

  • Paratypes: USNM068643, 1 of 6 whole-mounted worms; 068645, a longitudinally sectioned worm on 3 slides (1-3), part of a second sectioned worm on 1 slide (4), and a tail mounted whole (5); 068646, a longitudinal sectioned worm on 3 slides and a whole-mounted tail on 1 slide. All from the type locality, Wild Cat Spring, Forbes State Forest, Somerset Co., Pa. (holotype USNM00068641 examined briefly at USNM but not borrowed). (ref. ID; 6564)

    Eclipidrilus frigidus Eisen, 1881 (ref. ID; 1923, 6554) reported author and year? (ref. ID; 5939)

    Descriptions

    In the lectotype material, the spermathecal ampullae (170x220 µm) lie in X with the pores in IX. The spermathecal ducts have a thick layer of cells outside the muscle wall, which are presumably peritoneal. The ducts are 110 µm wide, with thin muscles 10 µm thick. The peritoneal layer also covers the ectal end of the spermathecal duct, which consists of a chamber 150 µm across with folded walls and a very thin muscle layer. The atrim extends as far as XVI. The prostate layer is thin. The muscular atrial wall is 30 µm thick; the lumen is 80 µm across in places. The epithelial lining of the atrium is exceedingly thin. The atrium extends from XVI to XIII, where it narrows to form an ejaculatory duct 40-70 µm wide with muscle wall 12-18 µm thick plus a thick peritoneal layer on the outside. The ejacratory duct is short and coiled in XIII, has a thick muscle wall and a distinct epithelial lining, and enters an extended part of a complex penial structure. For convinence, this will be termed the penis here, and its nature is discussed below. The ental end of the penis consists of a muscular wall 25 µm thick and a lining layer of spongy tissue 35 µm thick, continuous with the epithelial lining of the ejaculatory duct. There is what appears to be a cuticular lining or basement membrane to the lumen, which is coiled. The various layers appear to be attached to each other and the structure does not appear to be eversible. Only towards the ectal end of this portion of the duct is the long of the peila structure dose no appear to be eviesle. Only towards the ectal end of this portion of the duct is the lining of the penial structure detached from the wall and it therefore appears to be eversible. The ectal end of this part of the penis protrudes into a voluminous penial sac, which is inverted on one side of this specimen and partially everted on the other. At this point, where the penis forms almost pendant penis in the sac, there is a distinct cell layer. This distinct short set of modified cells appears to provide an anchoring point from which at least a part of the lining of the more ental section might be everted. Below this point, the penial sac appears to be eversible through the lips of the male pore. In section, these lips also have the appearance of a small pendant penis. The body-wall musculature sheaths the end of the penial mass outside the muscular wall of the penis itself. There is a retractor muscle that is attached to the dorsal body wall. Testes and male funnels of equal size are present in IX and X; large ovaries in XI extend into XII. In the new material (Fend collection) the spermathecal pores enter the voluminous ectal chamber via a wide opening, and the chambers have deeply folded walls that are capable of expansion. The wall of the spermathecal ampullae have tall vacuolated epithelial cells. The lining of the ental end of the penis is constructed of ill-defined cells with few nuclei, as in the lectotype, and the lumen is coiled within the duct. The atria and penes are coiled and therefore do not extend as far posteriad as in the lectotype. The atrium has muscular walls 15 µm thick and a lumen 190 µm across. The prostate layer is thin. The ejaculatory duct is only 32 µm wide, with a very small lumen and with muscles and epithelial layers about equally thick. The ejaculatory duct and part of the penis are covered with a single cell layer of tall vacuolated cells. The penis has a muscle layer 10 µm thick and is 100 µm wide. The specimen is mated, with masses of sperm in both the spermathecae and the atria. The coelom of IX and X is full of developing sperm, XI contains the large ovary and sperm sac, and there are egg sacs in XII and XIV and a sperm sac in XIII. In the LSU material, a dissected specimen has a spermatheca 100 µm wide with a wall 12 µm thick; the atrium is 130 µm wide with spiral muscular walls 35 µm thick and a wide lumen 60 µm across. The penial sac is 100 µm wide, with the muscle layers each 15 µm thick; the lining layers, 35 µm thick, are closely applied. In a mature specimen the spermathecal pores on IX lie in the setal line and have transverse slits surrounded by wide lips. The male pores appear to lie in a transverse groove some way posterior to the setae. In another specimen there is no groove. The lateral edges of the groove have wide lips. The atrium is 215 µm wide, with walls 40 µm thick, and extends into XV. In another specimen, the 2 slides, each bearing a dissected spermathecae, both have the spermathecal duct with a complex lumen that appears capable of considerable dilation. The ental end of the duct enters a wide chamber. The narrow ectal termination of the ampulla projects into this chamber, and the ampulla is 190-250 µm wide, full of sperm, and reaches XII. The slides bearing dissected atria and penes, and the sections, indicate that the histology of the penis changes halfway along its length. The ental end has densely staining material next to the narrow lumen, and the outer part of the lining appears more granular. At the ectal end, it appears as a separate narrow duct connected to the penial sac wall by fibers or contractile elements. In the sectioned material, near the ectal end of the penis the lining layer seems to be separated from the wall, as in the lectotype. This end protrudes into a final eversible chamber that leads to the male pore. (ref. ID; 6564)

    Remarks

    The penial structure does not appear to fit any simple definition of a pendant or eversible or protrusible penis. The ental end is a thick-walled tube in which the lining does not appear to be eversible. Towards the ectal end of this section the lumen appears coiled, and finally the lining cells lose contact with the body wall for a short distane and this section does appear to be eversible. In Fig.1B, the structure marked with an asterisk looks remarkably like a short pendant penis. The sac in which this hangs then everts through the male pore and appears to be a penis-like structure again. I refer to the whole structure lying ectal to the ejaculatory duct as a penis in this account for lack of any way to determine the function and origin of its parts. Wassell (1984) states that the peculiar lining of the penis is derived from the inner layer of the atrium pore, and that it is continuous with the longitudinal body-wall muscles anteriorly. The lining of the atrium is very thin, as in all these species, and it is certainly continuous with the lining of the penis through the ejaculatory duct. However, the histology changes quite rapidly. This layer must be continuous with the epidermis of the body wall, from purely theoretiacl cosiderations. The ectal part of the penis pore is lined with what appears to be a tube connected to the wall by fibers that might be contractile. Presumably this is the layer identified as continuous with the body-wall muscles. The details of this and other penes in the genus need careful study in well-fixed material, including ultrastructure investigation. In some lumbriculids the penis is said to be composed of elongations of atrial lining cells, in which the cell bodies are retained within the atrium. The body-wall musculature forms a small conical enclosure around the base of the penis and the penial sac, and this is also associated with well-developed septal muscles immediately posteriad to the pore. These presumably provide the retractor-muscle system that Wassell could not locate. The septum behind the spermathecal pore is also strongly developed. The LSU section series 1 is of no value. Series 2 and 3 are faded but have interesting sections of the gonopores. (ref. ID; 6564)

    Type materials

  • Lectotype: USNM00025565, alcohol specimen and 5 slides, 0-230a-e (0-230a-d are longitudinal sections, e is transverse sections). Three Springs Meadow, North Fork, Kings R., Fresno Co., Calif., 11 August 1878. G. Eisen. (ref. ID; 6564)
  • Other material: USNM00001210 (shown as non-types in catalogue as collected later than types), specimen in alcohol; USNM00032911, slide of dissected atrium and spermatheca, from USNM00001210, D.G. Cook. S. Fend collection: longitudinal sections on 5 slides plus whole-mounted tail. Big Spring nr. Bassets, Sierra Co., Calif., 6 August 1996. LSU collection: 3176, 12 unstained whole mounts in Canada balsam (9 immature, 2 partly mature, 3 mature, 1 mature dissected), one set of atria and spermathecae on 4 slides, 1 slide with two very small whole-mounted specimens, 1 slide with head and fragments whole-mounted, 1 slide with tail whole-mounted, three sets of longitudinal sections: series 1, 7 slides plus whole-mounted tail; series 2, 6 slides and whole-mounted tail; series 3, 6 sides and whole-mounted tail; all Veil Falls, Salmon R., Idaho, R.L. Denton, 1976. (ref. ID; 6564)

    Eclipidrilus ithys Brinkhurst, 1998 (ref. ID; 6564 original paper)

    Descriptions

    Length of fixed individuals 17-23 mm. Number of segments up to 122 (3 specimens 23 mm long had 78, 93, and 122 segments). Prostomium rounded, long, no proboscis. Diameter at clitellum 0.6 mm. Secondary annulation not prominent, some secondary annulation on IV-VIII. Clitellum from 1/2IX to 1/2XII. Setae simple-pointed, sigmoid. Setae of II 0.3 mm long, 0.01 µm broad behind nodulus, those of V 0.4 µm long, posteriorly as long but more strongly hooked. A pair of spermathecal pores situated behind the ventral setae of IX. A pair of male pores behind the ventral setae of X, set in prominent circular cups. Female pores in the intersegmental furrows of 10/11. Pharynx well-developed. Pharyngeal glands in III, IV, and slight in V. Small pair of testes in IX associated with small funnels on 9/10. A large pair of testes in X associated with large foled male funnels on 10/11. Ovaries very large, filling the free space of XI and extending posteriorly for several segments in some instances. Spermathecae with pear-shaped to cylindrical ampullae with walls thick at confluence of ampullae and ducts, and entally walls with large vacuolated cells. In a dissected specimen, spermathecae 0.4-0.5 mm long and 0.3 mm wide with ducts 0.2-0.3 mm long. Ampullae may be reflected forward or rearward into X. Spermathecal ducts distinct from ampullae, 37 µm wide, with thick muscle layer and epithelial layer and narrow lumen. The spermathecal pores are surrounded by a small glandular bulb. Ental part of atrium extends through XII-XIII and just to XIV, with relatively thin walls and a thin layer of clumped prostate glands cells. The atrial wall may be 25 µm thick and the lumen 50-100 µm wide. The wall/lumen/wall ratio varies (1/1/1 to (1/2)/1/(1/2)). Atria narrowing somewhat in XI to enter ejaculatory ducts that traverse the posterior end of X. The ejaculatory ducts widen before entering the narrow terminal portion that projects very slightly in the middle of cup-shaped protuberances. This projection appears as a tiny circular penis-like structure in surface view, but there are no true penes. The ejaculatory duct, including the swollen section, stands erect in X. There are thin muscles on either side of the vertical male duct. In dissected specimens the lining of the ejaculatory duct appears to be separated from the muscle layer, but this is not confirmed in the sections. There are no extensive glands around the male pore. Often only one atrium develops, although the male pore associated with the undeveloped atrium may be detected. This pore is associated with a clump of cells that appears to represent a rudimentary atrium. There is a small anterior sperm sac in VIII, otherwise sperm sacs may be present in parts of XI-XIV not occupied by atria. The egg sacs may be visible from XIV or more posteriad, and may extend for 4 segments. (ref. ID; 6564)

    Remarks

    The atrium in this species reaches the exterior through a narrow duct, as in the subgenus Leptodrilus Wassell, 1984, without the elaborate penial structures seen in the other subgenera. Eclipidrilus lacustris has single spermathecae and atria with median pores, both associated with small glands, Eclipidrilus fontanus has paired spermathecae and atria, and material described here indicates that both the male and spermathecal pores are associated with massive glands. The erect nature of the terminal part of the male duct of E. ithys is like that observed in E. lacustris and, to a lesser extent, E. fontanus. In E. ithys there are no separate glands by the gonopores apart from the bulb-like structure at the spermathecal pore. The gonopores are always paired even when one atrium is rudimentary. The variation in the number of atria in the new taxon should be noted. Of the specimens sectioned or dissected, 6 have one atrium and 5 have two. It is not possible to say if the atrium is always lost from the same side of the worm. This is important in regard to the separation of other species based on this degree of variation, which will be discussed in regard to the genus as a whole. (ref. ID; 6564)

    Etymology

    ithys (Greek) for the straight, upright termination to the male duct. (ref. ID; 6564)

    Type locality

    Spicket River, Lawrence, Mass., U.S.A., 485 mi above the confluence of the river with the Merrimack R., between Leonard School and General Hospital, 42 degrees 42'33"N, 71 degrees 9'33"W, June 1966, coll. D. Grasso and B. Wamsley. (ref. ID; 6564)

    Type materials

  • Holotype: USNM176996, a longitudinal serially sectioned specimen on 2 slides, with the tail whole-mounted in Canada balsam. (ref. ID; 6564)
  • Paratypes: USNM176997-177003, 4 serially sectioned specimen in Canada balsam, 1 dissected specimen in Permount, 6 mature and 9 immature specimens in 70% alcohol, from the type locality, coll. D. Grasso, B. Wamsley and R.D. Kathman. (ref. ID; 6564)
  • Other material: 1 specimen divided sagittally, in 70% alcohol, 19 immature specimens on 9 slides in CMCP, 26-27 October 1995, and 1 dissected specimen in Permount, 26-27 October 1995. One specimen serially sectioned, 6 dissected specimens in CMCP, 1 dissected and 1 anterior end whole-mounted in Permount, 28 May 1996, and 10 mature and 7 immature specimens in 70% alcohol, 5 October 1996. All from the type locality, coll. R.D. Kathman. (ref. ID; 6564)

    Eclipidrilus lacustris (Verrill, 1871) (ref. ID; 6564) reported author and year? (ref. ID; 5939)

    Descriptions

    In the two paralectotype slides examined in detail (0-12a, b), the single longitudinally sectioned worm has spermathecal pores just to the side of the nerve cord in VIII and IX. The ampulla of the anterior spermatheca lies mostly in VII, that of the second lies mostly in IX. The ampullae are about 450 µm x 650 µm, the epithelial cells 5 µm thick. The ducts are distinct, about 60 µm wide, with very thin muscle layers but an outer glandular layer. There is a slight modification of the body wall around the spermathecal pores. A group of gland cells was observed on the outer lateral side of the spermathecal duct in the lectotype, and the nerve cord is displaced. The atrium is more than 1 mm long, with muscular walls 80 µm thick and a lumen 70-100 µm wide. There is a thick layer of prostate cells on the atrium. The atrium narrows abruptly to a twisted ejaculatory duct that enters a vertical terminal portion standing half as high as the segment in X. At the pore the male duct is 40-45 µm in width. The terminal part of the male duct appears to protrude between lips that presumably encircle it. The terminal portion of the duct appears to lie within a small penial sac, and the epithelial lining is separated from the muscle layer and forms a distinct tube within it. These may be postmortem changes, as the material was not well fixed. The same separation of layers was been in transverse sections. The terminal part of the male duct is sheathed in thin muscle strands. There is a very small collection of glandular cells in front of the pore. The anterior male funnels are open and functional, but small, whereas the posterior male funnels are very large and convoluted, reflected into XI above the atrium. The ovary is large, extending into XII. In the Bala Lake material, the spermathecae have ampullae at least 360 µm wide, with a thin-walled ectal ampulla and a thick-walled ental ampulla. The distinct ducts are 50-60 µm wide and the muscle layer is thin. The ducts terminate in glandular pads. The spermathecal pore is almost median and on the opposite side of the nerve cord to the male pore. The atrial walls are 45 µm thick, with a lumen 80 µm wide in places. The atrium is at least 1.3 mm long. The prostate layer is thick. The ejaculatory duct at its origin is 70 µm wide, the muscular walls 20-30 µm, the epithelium thin, and the lumen only 20 µm wide at most. At the male pore the dimensions are as follows: width 30-45 µm, muscle layer 15 µm thick, and epithelium 10 µm thick with a very narrow lumen. There are glands around the male pore, especially on the side of the nerve cord opposite the male pore where the second male pore would be located if they were paired. The pore opens into the outer edge of a narrow, slit-like depression in the body wall. In one specimen the pore is inverted, whereas it is everted in the paralectotype examined. The Cayuga Lake specimen has distinct glands around the spermathecal pore and the ampullae have thick walls of vacuolated cells throughout, with only an indication of a thin-walled proximal part. The specimen is unmated. The atrium (in the second set of sections) is typical. In the Mountana specimens, examined as unstained whole mounts, the spermathecal and male pore are median as usual. In one specimen, they are located in VII and VIII and in the other in IX and X as usual. Measurements are approximate because of the nature of the material. The spermathecal ducts are about 70 µm wide and at least 250 µm long. The paired spermathecal ampullae differ, one is 500 x 375 µm and the other about 650 µm square. The atria are 650 µm long to the beginning of the ejaculatory duct. The muscular walls are 75 µm thick and the lumen averages about 90 µm across. The male pores open into an oval area, the termination of the ejaculatory duct being erect in one specimen, and about 200 µm tall and 70 µm wide at the widest point above the male pore, 35 µm wide at the pore. The North Carolina specimen has an atrium 1.4 mm x 0.4 mm; the duct is straight in the dissection, 1.25 mm long x 40 µm wide, widening to perhaps 60 µm at the ectal end. (ref. ID; 6564)

    Remarks

    The 3 slides of the lectotype series examined consist of very broken, faded transverse sections. The paralectotype series contains 19 slides and worms in alcohol according to the USNM catalogue. Two of these were examined in detail, as described above. All of the known specimens have single spermathecae and atria with median pores. This species was originally collected in Lake Superior (Saint Ignace Island). This species was recorded in a regulated lake (Bala Lake) in Wales by Cook (1969). Bala Lake forms the source of the River Dee, which drains into the Irish Sea not very far from Liverpool and the Manchester Ship Canal, which used to be the main trading port from Britain to North America. A much earlier seaport was located closer to the mouth of the Dee itself. Transport of the species up to the headwaters of the Dee from these sources seems improbable. (ref. ID; 6564)

    Type materials

  • Lectotype: USNM15589, transverse sections (68b, e, f), St. Ignace Island, Lake Superior. These slides are quoted by Wassell as 15587. Paralectotype: USNM 17947, a longitudinally sectioned worm on 2 slides (0-12a, b); 17947, longitudinal sections (0-480b, c, D.G. Cook); 32667, blood vessels, whole-mounted (from 17947, D.G. Cook).
  • Other material: D.L. Gustafson collection: 2 mature and 2 immature specimens on 1 slide, west fork, Bitter Root R. below dam, Ravalli Co., Mont., U.S.A., 5 October 1996. R.O. Brinkhurst collection: 7 slides of sectioned worms (A1-A3, B1-B4), Bala Lake (Llyn Tegid), Wales (Cook 1969). M. Winnell collection: 1 mature dissected worm, Tranters Creek, tributary of the Pamlico R. (near Washington, D.C.), N.C., U.S.A., May 1992. LSU collection: LSU 3177, 1 specimen cut in two pieces used to make two sets of longitudinal sections (now labeled a and b), on 6 slides each, Cayuga Lake, N.Y., Stn. 31-41, pump, 23 May 1975, D.R. Spencer. (ref. ID; 6564)

    Eclipidrilus palustris (Smith, 1900) (ref. ID; 6564) reported author and year? (ref. ID; 5939)

    Descriptions

    In the type material, the spermatheca are long, extending as far as XV unless coiled. The ectal part of the ampulla is about 150 µm across, with a thin wall 30 µm thick; the ental part is of about the same width but the wall is twice as thick, with large vacuolated cells. The ampulla leads to a duct 80-100 µm wide. This duct has a thick layer of peritoneal cells outside the thin muscle layer, and a folded lining layer. The spermathecal pores have large muscular vestibuli 100 µm wide and the anterior edge has a large muscle running dorsad to septum 8/9. The elongate atrium drains through a narrow ejaculatory duct that run posteriad to the apec of a long penial sac. The penial sac contains a thin penis that can be folded with in the sac, but the sac is characteristically curved from its origin close to the dorsal body wall (in XIII in most instances) down to the male pore. The atrium has a muscular wall varying from 60 to 90 µm thick and a lumen 50-70 µm wide. The atrium extend posteriad to XV ot XVI. The prostate layer is thin. The lining layer is thin but distinct. The ejaculatory duct diameter varies from 75-70 µm and its wall consists of a thick muscle layer and thin lining. The penial sac is 150-200 µm wide, gradually narrowing ectally. The penis is thin, 60-80 µm thick in the sac, and only 30 µm where extended. It consists of a thin wall with flat nuclei that is attached to the inner tissue by thin trabeculae. The male pore is complex. The body wall and the end of the penial sac form what might be mistaken for a small pendant penis but for the thin true penis emerging from the opening of the sac. The distal end of the penial sac is surrounded by muscle tissue. The pores are somehwhat median to the ventral chaetae. There is a thick muscle band running from the anterior edge of the muscular mass of the male pore to the dorsal body wall. There are two pairs of male funnels but the anterior pair is small and only the posterior pair of testes is present. The LSU material from Florida is essentially similar to the type series. The immature whole mount has a developing spermatheca which is a tall cylindrical group muscles. The male duct is also a cylinder of undifferentiated cells at this state, but twice as long and nearly as long as the body diameter. In a mature specimen the atrial walls are 70-75 µm thick and the lumen 100 µm wide. The atrium extends to XVI. (ref. ID; 6564)

    Remarks

    Part of the structure of the penis is clear, but the innermost layers do not form a simple tube. The very thin outer wall is connected to the inner cellular material by thin trabeculae. In some specimen where the penis is everted, it forms a whiplike structure as long as the penial sac. It seems probable that the penis itself is also eversible rather than simply protrusible, because the penial sac is incapable of being contracted sufficiently to account for the length of the extended penis, even though it has large retractor (or retainer?) muscles at the ental end. The penis is clearly elongated in some manner when extended outside the penial sac. (ref. ID; 6564)

    Type materials

  • Syntypes: USNM00025509, 3 vials and 17 slides, series 0-168a-c (2504-6, old catalogue) longitudinal sections; 0-167a-g (2507-13), transverse sections; 0-167Ba-c (2514-16), longitudinal sections; 0-167Bd-f (2517-19), transverse sections; 1 dissected whole mount labeled "Plesiotype," Cook, D.G., all Polk Co., Fla., March 1897, coll. A. Hempel, det. F. Smith (as Mesoporodrilus). (ref. ID; 6564)
  • Other material: LSU1490, whole mount, semimature worm, Peace R., Polk Co., Fla., at U.S.90, 2 mi E of Barlow, M. Loden, 7 September 1975; 1949, 8-slide series of longitudinal sections, only 1 seen, stream, Desoto Co., Fla., at FL 72, 2.3 mi E of Sarasota Co. line, M. Loden and G. Landry, 11 March 1978; 2156, whole mount with atrium and one spermatheca dissected out, stream in Calhoun Co., Fla., at FL 20, 5.9 mi E of Bay Co., line, M. Loden and J.T. Wassell, 4 November 1978. (ref. ID; 6564)