CHARACTERS OF THE MOLLUSCA. 5 



than another ; certainly the mollusca are not the least so, for 

 their numbers in species and individuals are proof of a propor- 

 tionate influence in the animal kingdom ; * their complexity of 

 organisation claims for them a considerable rank in its roll; and 

 the many notable peculiarities of structure in their nervous 

 system, in their circulatory apparatus, in their secretions, and 

 in their generative system, recommend them in a lively manner 

 to the comparative anatomist and physiologist. It was in 

 such investigations that Cuvier laid the foundation of his 

 immortal fame ; and the results of them he has recorded in 

 a work which has become one of the Conchologist's most 

 valued classics. I mention it now as a proof that you have 

 engaged in no worthless or trifling pursuit, and a stronger one 

 I cannot give ; for, after Cuvier had attained a reputation 

 surpassed by no cotemporary philosopher, he thus speaks of 

 his first studies, and thus invites you to their participation : 

 if, says he, in allusion to the work just mentioned, " these 

 Memoires have no other effect than to direct the attention of 

 others to the singular peculiarities which the history of mol- 

 luscous animals offers to their notice, I shall have done well, 

 and be repaid for the toil of my task ! " We honour ourselves 

 in accepting the invitation of such a man. 



It was Cuvier who, first of all, gathered together these 

 animals, hitherto scattered among many classes, and assigned 

 to the group or subkingdom the denomination of Mollusca, 

 a term in previous use, but which had been very vaguely 

 defined and applied. They are so named because they have 

 soft fleshy bodies, devoid of bones. They are readily distin- 

 guished from all above them in the animal kingdom by the 

 want of an interior skeleton, and by the colourless condition 

 of their blood ; and from insects and worms they are distin- 

 guished with equal facility, for the body of the Mollusca is 

 never divided, like that of insects and worms, into rings, nor 

 invested with a hard crust or skin, fitted like a coat of mail, 

 to the junctures, nor even furnished with jointed limbs and 

 organs of progression. On the contrary, the Mollusca have a 

 soft undivided body, covered with an irritable mucous skin, 

 moistened with a viscous liquor, which exudes from it : this 

 skin, in very many instances, is ample enough to be formed 

 into membranes and fleshy folds, and hence assumes somewhat 



* "The number of Mollusks already in collections, probably reaches 

 8,000 or 10,000. There are collections of marine shells, bivalve and uni- 

 valve, which amount to 5,000 or 6,000 ; and collections of land and fluviatile 

 shells, which count as many as 2,000. The total number of Mollusks would 

 therefore probably exceed 15,000 species."— Agassiz and Gould's Princ. of 

 Zoology, i. p. 3. 1848. 



