| OCR Text |
Show 700 MR. F. E. BEDDARD ON N E W [Dec. 20, cells serving as nutritive cells to the developing ova; the oviducts are peculiar in that they perforate the septum dividiny segments xiii./xiv. twice. The funnel opens freely into the interior of segment xiii. right opposite the ovary and also into the interior of the egg-sac ; it then passes into the cavity of the thirteenth segment and bending back runs straight along the body-wall up to its point of opening on to the exterior. The oviduct has thus an unusually long course, which is further increased by the fact that the pore is situated near to the hinder end of the fourteenth segment; the calibre of the oviduct is considerably greater than that of the sperm-duct ; the two can be easily compared in this respect, as the sperm-duct passes close to the oviduct; the oviduct is not ensheathed in a muscular coat; the ciliated epithelium is only covered by a delicate peritoneal layer. The ovaries lie in the thirteenth segment, attached, as is usual, to the front wall of that segment. The septum dividing segments xii./xiii. joins that which follows, and a sac is thus formed which encloses the ovaries and the terminal bulbus of the spermatotheca. Centrally this sac is almost filled by the bulbus, but laterally there is plenty of room, and the spacious cavity thus formed is occupied not only by the ovaries and detached ova, but also by an immense quantity of small nucleated, often fusiform corpuscles; similar corpuscles are also found in great abundance in the xith segment. I am doubtful whether to regard these as slightly metamorphosed cells of the ovary and testis respectively or merely as perivisceral corpuscles, which happen to have been aggregated together in greater numbers in the two segments referred to than elsewhere. The ripe ova (from the egg-sac) have no striated membrane such as is found in certain other Eudrilids. This worm evidently belongs to one of the more simply organized of tbe Eudrilidae ; for the fusion of the female organs is incomplete. It must therefore be referred to one of the following genera, viz. Eudriloides, Platydrilus, Meyachceta, Reithrodrilus, or Notykus. As to external characters it agrees with Platydrilus in having a saddle-shaped clitellum, and also in the extent ot the clitellum. The internal anatomy is in some respects unlike any of these genera ; for instance, the peculiar form of the calciferous glands marks out the present species from all Eudrilidae including those mentioned, in none of which are there calciferous glands at all. In possessing one pair of testes and in the corresponding single funnels &c. the worm resembles Notyhis, Eudriloides, Megachceta '{; but this is not of course an important difference from Platydrilus &c. The complete fusion of the two atria is peculiar to the worm, though a commencing fusion occurs in Eudriloides, from which, however, the species described here differs in the shortness of the atria and in the absence of a muscular tunic. The principal reason which leads me to refer the worm to the genus Eudriloides is the structure of the female organs. 1 have described the modification of the septum dividing segments xiii./xiv., which forms a sac enclosing the terminal part of the spermatothecal sac and the ovaries and oviducal funnels: |
