160 



MR. Gh E. DOBSOtf ON APLYSIA. DACTY/LOMELA. 



than the right; and this inequality is continued throughout the 

 series*. 



Fig. 1. 



Lingual teeth of Aplysia dactylomela, X 58 diam. 



The mandibles, or labial plates, are invested internally with a 

 rough leathery substance, which, as seen by a | objective, con- 

 sists of indurated cylindrical rod-like bodies, imbricated, with 

 rounded extremities, forming a depressed pile, very similar to the 

 corresponding structure in Triton. 



Fig. 2. 



Gizzard of A. dactylomela cut open, showing position and relative sizes of 



spines (natural size). 



The gizzard is armed with about thirty-three horny tooth-like 

 spines, the arrangement of which is shown in fig. 2, a, above, where 

 the position of their bases is indicated. The leading forms of 

 these spines are shown at b and c, where two of the largest are 

 figured of the natural size. The very capacious stomach of the 

 animal was found to be filled with undigested food, consisting 

 chiefly of a minute species of Algse. 



* As in other species of Gasteropoda, an abnormality occurring in one of the 

 lingual teeth is repeated in the longitudinal series to which it belongs. 



