| OCR Text |
Show 442 MR. F. E. BEDDARD ON THE [Nov. 5, Perrier, loc. cit. pi. i. fig. 1) is not clearly defined. In the sexual individuals studied by myself the last segment was only furnished with the ventral bundles of setae. This character may possibly prove to be of specific value. It is of some importance to note that budding and sexual reproduction do not take place concurrently in Dero, since d'Udekem has asserted that they do in some allied forms. Among the specimens of Dero which I examined were a few individuals which agreed in every particular with the others except for the entire absence of all traces of the branchial apparatus. There was, moreover, no appearance of any injury to this part of the body, and the segments ended off in a perfectly regular fashion. I do not believe that these individuals were a species of Nais or any other Fig. 2. Clitellar epithelium of Dero. a. Showing granules in cells of developing clitellum ; b. Fully mature cells, surface view ; c. Fully mature cells showing crenated margin, surface view ; d. Section showing granular coagulum which accumulates between epithelium and cuticle. described allied genus, but I hope to be able to reinvestigate the point if I succeed in keeping the brood of Dero alive. I now pass to the description of the generative organs. Clitellum.-This modified region of the epidermis was very conspicuous in fully mature individuals by its somewhat greater opacity. Its anterior limits are as nearly as possible bounded by the apertures of the spermathecae (see fig. 1), posteriorly it extends beyond the 5th seta-bundles ; the clitellum therefore occupies three segments, |
