1869.] On the genus Onchidium. Ill 



go. (in fig. 1. c) middle genital pore. 



/.—foot. 



d. — dorsal part of the mantle. 



vd.— vas deferens. 



vdo. — opening by which the external vas deferens enters the body. 



ba, in fig. 5. — buccal appendage. 



tp. — external covering of the eye-pedicle. 



ov. — oviduct. 



PL XIY. 



Fig. 1, 1 a, 1 b, 1 c, dorsal, ventral, side and front views of Onch. 

 typhce ; the figure between 1 and 1 a, represents the eye-pedicle, iso- 

 lated and enlarged. 



Fig. 2. A large specimen of Onch. typhce, cut open along the centre 

 of the back, the internal organs being exposed. 



Fig. 3. A small portion of the edge of the mantle showing the 

 internal cavities. 



Fig. 4. (Esophagus, cut open, with the radula, salivary glands, (fee. 



Fig. 5. Internal organisation of Onch. typhce. 



Fig. 6, radula, 6 a, central and a few lateral teeth, 6 b, side view 

 of the central, and 6 c side view of the lateral tooth ; all greatly 

 enlarged. 



PL XV. 



Fig. 1, and 1 a, dorsal, and ventral, views of 0. pallidum ; 1 b, 

 radula, 1 d, central and lateral teeth, 1 e, side view of a lateral tooth ;. 



Fig. 2, 2 », 2 b, dorsal, side, and ventral, views of 0. tigrinum ; 

 2 c, radula ; 2 d, central and lateral teeth ; 2 e, side view of a central, 

 2/, side view of a lateral tooth. 



Fig. 3, 3 a, 3 b, 3 g, dorsal, ventral, side, and front, views of O. 

 tenerum ; 3 c, radula, 3 d, central and lateral teeth, 3 e, side view 

 of a central, 3 f, side and front views of a lateral tooth. 



N. B. — The figures of the teeth are in all cases enlarged. 



