78 



Natural History of Molluscous Animals ; — 



a fresh material [Man. de Malacol., p. 177.) : but the conclu- 

 sion is a hasty one ; for I, at least, am not inclined to attach 

 that value to deductions of this kind which many seem to 

 think they merit, The Aplysia has very small obtuse man- 

 dibles, of a soft cartilaginous substance ; yet that mollusc eats 

 its sea weed bit by bit, and nips away a portion from a large 

 frond as easily as the Tritonia can be supposed to do. # It 

 is not unlikely, however, that those jawless species which pos- 

 sess the spinous tongue may take their food by rasping it off 

 the surface by aid of the prickles; for it may be remarked 

 that the Patellae and the periwinkles, when active, are con- 

 stantly protruding the anterior portion of the tongue between 

 the lips, and withdrawing it in rapid succession. 



The liver appears to be proportionally greater in these 

 tribes, in relation to the other viscera, than in the zoophagous 

 Mollusca; and, unlike that of the acephalous Mollusca, it 

 rarely envelopes the stomach. It occupies, very generally, a 

 backward position among the viscera, filling the upper con- 

 volutions of the shell ; and it is composed of lobes and lobules f, 

 of which the ultimate are in the form of hollow globules, in 

 each of which a biliary vessel originates. These vessels, by 

 successive reunions, contribute to form one, three, or four 

 large canals, which open directly into the stomach, and pour 

 in, we may presume, a large quantity of bile ; essential, appa- 

 rently, to the rapid digestion and assimilation of the food. 

 Sometimes the biliary pores, as in Doris, are so large, that 

 Cuvier wonders by what means the food is prevented entering 

 them (Mem. sur le Doris, p. 15.) ; but, according to Professor 

 Grant, it actually does enter and fill them. " Upon opening 

 the cavity of the stomach," says this distinguished naturalist, 

 " we see, as in the tunicated animals, and in the inhabitants 



* Although no doubt 

 can be entertained that 

 Tritonia is really her- 

 bivorous, yet it seems 

 sometimes to indulge in 

 other food ; for I took 

 from the stomach of 

 one some curious bo- 

 dies, of which I annex 

 magnified figures, and 

 which appear to be the 

 fry of Jsterias papposa. Fig. 10. the upper, fig. 1 1. the under surface. 



•f Swammerdam says it is divided into lobes, " according to the differ- 

 ent course of the intestines, which make as many divisions in it as they 

 have turnings and windings." Our description of the liver is derived from 

 Blainville, Man. de Malacologie, p. 123. 



