1869.J 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. 



PI. XIV. 



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

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

 lated and enlarged. 



Fig. 2. A large specimen of Onch. typhcd, 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, &c. 



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 a, 2 i, dorsal, side, and ventral, views of O. 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. 



