OCR Text |
Show 1897.] FROM SOUTH AFRICA. 341 the glandular cells is a regular fringe of spermatozoa. There are two pairs of sperm-duct funnels in segments x., xi.; corresponding to these are three pairs of sperm-sacs wdiich lie in segments x., xi., xii. There is a single penial seta to each spermiducal gland ; it is slightly notched at the extremity. In the intestine of this worm I found numerous examples of an Infusorian belonging, or allied, to the genus Opalina, so frequent a parasite of the Oligochaeta. (4) Acanthodrilus falcatus, n. sp. Of this new form Mr. Pureed collected no less than 56 examples from " Cape Flats ; in w-et sand on edge of a small vley between Retreat Station and Zeekoe Vley." The species is not a large one; an individual which appeared to be quite typical measured 70 m m . by 3 m m . in breadth : it had rather more than 100 segments, but the mode of preparation (with corrosive sublimate) rendered the number of the segments a little difficult to ascertain with accuracy here and there. The posterior segments are noted to have been during life blackish. The prostomium did not divide the first segment; it had rather the appearance of being simply a continuation of it, just indenting in a semicircle its front margin. The ventral setce, as in other species, are nearer to each other than the lateral; and the two setae of the ventral rows converge slightly at the male pores. The clitellum occupies segments xiii .-xvi. Genital paplllce are present and vary somewhat in number in individuals. I found them to be present in not fully mature individuals as well as in those with a clitellum. On segments x., xi. were a single median papilla, or rather on the first of these two segments a closely approximated pair; on the xith segment the single papilla was seen on a closer examination to be composed of tw?o fused papillae. On xvi. and on xix. there was also a median papilla. There is a slight gizzard; the intestine begins in segment xvi. The spermathecce show some variation. The oval pouch has at least two very white sausage-shaped diverticula which are of considerable length. In the case of one spermatheca there was a third smaller diverticulum. In one worm each spermatheca had three diverticula, and in one spermatheca of this individual there were as many as four. The spermathecae open on to the exterior in front of seta 2. There are two pairs of sperm-duct funnels in x. and xi. The sperm-sacs are in segments ix.-xii. The spermiducal glands are provided with, penial setce,. The actual extremity of the seta is much hooked (wdiencethe specific name of the worm) and is free from denticulations or ridges. Immediately in front of this the seta is much wider and is furnished for quite a short space with ridges, as in so many other species of Acanthodrilus. |