1^85.] 



NEW-ZEALAND EARTHWORMS. 



815 



different segments, the communication of the transverse liearts with 

 the supra-intestinal vessel, &c. 



The clitellum in Acanthodrilus, as in many other Earthworms, is 

 saddle-shaped ; the only otlier form of clitellum met with is in 



Acanthodrihts nova sclandia. — Anterior rcgiou of body from ventral surfece. 



cl. clitellum. A. mnle PfinpraHvp nnfirtnrps ■ i"n nnprturpH ni />nniil!itnr' 



clitellum, (J, male generative apertures; 



of tl, 



ciiuiii, (3 , luaie generanve aperuires ; c.p. apertures of copulatory 

 pouches ; J, female generative aperture, veith long penial setfe. 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 

 segmenls, which are only partially occupied by the extension of the 

 clitellum. 



such forms as Perichceta, where the clitellum completely encircles the 

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

 in this genus to hear some relation to the development of the male 

 generative orifices : it ceases to exist where these structures are 



53* 



