1685.] 



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 onlv other form of clitellum met with is in 



C.p, 



H 



Fig. 1. 



^/ \\ 



-J'f 



// 



V 



/' 



\\ 



Cl" 



J>i- 



Acanthodrilus, nova zclandlce. — Anterior region of body from ventral surface. 



cl. clitellum, ,^ , male generative apertures; c.-p. apertures of copulatory 

 pouches ; J, female generative aperture, with long penial setae. Inside 

 of 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 Perichceta, where the clitellum completely encircles the 

 whole body. The peculiar form of the clitellum appears, however, 

 in this genns to bear some relation to the development of the male 

 generative orifices ; it ceases to exist where these structures are 



53* 



