§ XI. COLLECTION OF UN ARTICULATED 

 INVERTEBRATED ANIMALS: 



COMPREHENDING THE SHELLS, THE ECHINI, AND THE POLYPI. 



The lovers of natural history have at all times 

 taken pleasure in forming collections of shells, 

 on account of the elegance of their forms and 

 the beauty of their colours ; but these collections 

 were objects only of luxury and of curiosity. 

 As none but the most brilliant and rare shells 

 were sought after, as their characters were even 

 altered in order to augment their beauty by po- 

 lishing them, and as the animals to which they 

 belonged were not thought of, they were use- 

 less in zoology. But this is no longer the case; 

 the researches of M. dc Lamarck on conchology 

 have proved, that the characters of a shell indi- 

 cate those of the animal to which it belonged, 

 as the genus of a quadruped is indicated by its 

 teeth. 



The distinction between terrestrial, river and 

 sea-shells, and the comparison of those belonging 

 to living subjects with those in a fossil state in 



