336 PHYTIVOROUS MOLLUSCA. 



vourer raises and shakes his papillae in the manner that the 

 porcupine shakes its quills when irritated, and then, laying 

 back the dorsal tentacles, and curling up the oral ones, fixes 

 the protruded mouth and jaws upon his prey, when, with 

 a convulsive shrinking up of the body, morsel after morsel 

 is appropriated. In this manner it is not uncommon to see 

 an individual entirely devour another, half its own size. 

 We have also seen this species feed upon a Lucernaria." * 



So also the pulmonated Gasteropods have a strange han- 

 kering after flesh, and become very cannibals in satisfying 

 this propensity. Lister asserts that snails will eat not only 

 bread and cheese, but flesh of all kinds, particularly fish and 

 salted meat ; -f and, in another place, he tells us that, having 

 once placed an individual of the Helix aspersa with another 

 of the Arion ater in a vessel together, he found, on the fol- 

 lowing day, that the former had slain the slug, and had 

 miserably torn and eaten its skin, " tantus animus est etiam 

 pigerrimis animalibus.";}; I have repeatedly seen the Black 

 Slug (Arion ater) feeding on individuals of its own species 

 which had been accidentally crushed, and were yet scarcely 

 dead ; and the observations of Mr. Power, which have been 

 since confirmed, show that they feed voluntarily on earth- 

 worms, dead or dying. Of the aquatic tribes, we are in- 

 formed by Mr. Jeffi'eys, that " the food of the Limnei is 

 animal and vegetable matter in diflerent states of putridity ; 

 which makes them deserve the perhaps not unapt epithet of 

 ' scavengers of the waters.' In the absence of other nourish- 

 ment, they will even devour each other, piercing the shell 

 near its apex, and eating away the upper folds of its inha- 

 bitant. This accounts for the mutilated and often imper- 

 fectly repaired state of the upper volutions of some speci- 

 mens." § 



Relative to the times when molluscous animals feed, a 

 very few facts only have been ascertained. Among the 

 earlier naturalists it seems to have been a prevalent belief, 

 that oysters and other bivalves were fat and in season at the 

 full moon, and lean and out of season at the new moon.|| A. 

 Gellius tells a story pat to the purpose : — " The poet Anni- 

 anus, on his Falerian estate, was wont to spend the time of 

 vintage in a jovial and agreeable way ; and he had invited 



* Brit. Nudibranch. Mollusca, pt. ii. ]>!. 12 and 15. 

 + Exer. Anat. de Coch. 90. See also Mag. Nat. Hist. viii. 80. 

 X Anim. Ang. p. 114. 

 § Lin. Trans, xvi. 371. 



II "Ostreis ct conchyliis omnibus contingit, ut cum luna paritcr crcscant, 

 pariterque decrcscant." — Cicero, De Div. ii. 14. 



