GASTEEOPODOUS MOLLUSCA. 



169 



or true cliylific membranous stomach ; the second chamber is 

 i by a muscular gutter, leading from the first to the 

 third stomach. 



The digestive organs of Aplysia Camelus (sea hare, fig. 1/7) 

 are not less singular, 

 being not only equally 

 complex, but in addi- 

 tion, having the inter- 

 nal membrane of the 

 second stomach, or giz- 

 zard, armed with carti- 

 laginous bodies. The 

 pharynx (a) is large and 

 muscular ; the straight 

 esophagus (b) having 

 traversed the nervous 

 collar (m), soon dilates 

 into an ample membra- 

 nous crop (o y o), turned 

 into a semilunar form. 

 This leads into a strong 

 muscular gizzard (p), 

 internally armed with 

 rhomboidal semi-cartila- 

 ginous plates, their ac- 

 tion being analogous to 

 the teeth found in the 

 stomach of the lobster, 

 and, like them, perform- 

 ing a similar bruising 

 function. This muscu- 

 lo-cartilaginous organ 

 opens into a third chy 

 lific stomach (q), the in- 

 ternal surface of which 

 is furnished with sharp recurved horny spines, most numerous 

 around the pyloric orifice ; into this region of the canal the 

 ducts from the liver (u, u), and the termination of a glandular 

 ceecal appendage, the pancreas, pour their secretions. It is 

 L mely interesting, in a physiological point of view, to study 



Fig. 177. The anatomy of the Aplysia 

 Camelus. 



