OCR Text |
Show 1885.] NEW-ZEALAND EARTHWORMS. 815 different segments, the communication of the transverse hearts with the supra-intestinal vessel, &c. The clitellum in Acanthodrilus, as in many other Earthworms, is saddle-shaped; the only other form of clitellum met with is' in Fig. 1. Acanthodrilus nova zelandice.-Anterior region of body from ventral surface. cl. clitellum, <$, male generative apertures; cp. apertures of copulatory pouches ; 5, female generative aperture, with long peDial seta;. Inside ot the generative apertures is a line which marks the boundary of glandular region of clitellum ; this is not continued on to 12th and 19th segments, which are only partially occupied by the extension of the clitellum. such forms as Perichata, where the clitellum completely encircles the whole body. The peculiar form of the clitellum appears, however, in this genus to bear some relation to the development of the male generative orifices; it ceases to exist where these structures are 53* |