HABITS AND ECONOMY OF THE MOLLUSCA. 13 



coral bed, and of the calyptrcea 9 fettered to its birth-place by its 

 calcarious foot. 



The carnivorous tribes prey chiefly on other shell-fish, or on 

 zoophytes ; since, with the exception of the cuttle-fishes, their 

 organization scarcely adapts them for pursuing and destroying 

 other classes of animals. One remarkable exception is formed by 

 the stylina, which lives parasitically on the star-fish and sea- 

 urchin ; and another by the testacelle, which preys on the com- 

 mon earth-worm, following it in its burrow, and wearing a 

 buckler, which protects it in the rear. 



Most of the siphonated univalves are animal-feeders ; the 

 carrion-eating stromb and whelk consume the fishes and other 

 creatures whose remains are always plentiful on rough and 

 rocky coasts. Many wage war on their own relatives, and take 

 them by assault ; the bivalve may close, and the operculated 

 nerite retire into his home, but the enemy, with rasp-like tongue, 

 armed with silicious teeth, files a hole through the shell, vain 

 shield where instinct guides the attack ! Of the myriads of small 

 shells which the sea heaps up in every sheltered " ness," a large 

 proportion will be found thus bored by the whelks and purples ; 

 and in fossil shell-beds, such as that in the Touraine, nearly half 

 the bivalves and sea-snails are perforated, the relics of antedi- 

 luvian banquets. 



This is on the shore, or on the bed of the sea; far away 

 from land the carinaria and firola pursue the floating acalephe ; 

 and the argonaut, with his relative the spirula, both carnivorous, 

 are found in the " high seas," in almost every quarter of the 

 globe. The most active and rapacious of all are the calamaries 

 and cuttles, who vindicate their high position in the naturalists' 

 " system," by preying even on fishes. 



As the shell-fish are great eaters, so in their turn they afford 

 food to many other creatures ; fulfilling the universal law of eat- 

 ing, and being eaten. Civilized man still swallows the oyster, 

 although snails are no longer reckoned " a dainty dish ;" mussels, 

 cockles, and periwinkles are in great esteem with children and 



