16 CLA.SS MOLLUSCA. 



portion of its body, that in which the most material or- 

 gans of the animal are found, namely, the heart and 

 the branchiae, or organs of breathing. These are most 

 curiously placed on the upper part of its body, projecting 

 from it and protected by a delicately white and trans- 

 parent shell, shaped like a little cap, and of a substance 

 resembling glass. The creature is able to enlarge its 

 body by filling it with water, and in swimming the back 



THE GLASSY cARiNARiA, (Carlnavia vitrca.) 



is undermost. The shell, which seldom exceeds an inch 

 in length, has been sought after by collectors with great 

 assiduity, and has, at times, fetched as much as ten 

 guineas at a sale ; a perfect specimen is very rarely met 

 with. There is a wax model of one of these shells in 

 the British Museum, nearly two inches wide. 



ORDER CEPHALOPODA. 



The Cephalopods have been so named by Cuvier, from 

 being furnished with a kind of inarticulated arms which 

 surround the head. We find among this class some of 

 the most singular productions of the waters ; they differ 

 materially from each other, and have been separated 



