CLASSIFICATION. 



LINNjEUS ranks Testacea as the third order in his 

 sixth class of animals called Worms. He has made three 

 principal or grand divisions, viz. 



MULTIVALVES, BIVALVES, AND UNIVALVES. 



The latter division he has subdivided, as will be seen 

 in the sequel. — It may be proper to acquaint the reader, 

 that, throughout this work, his system has been adopted. 



TESTACEA. 



MOLLUSCA COVERED WITH A SHELL. 



I. MULTIVALVES. 



Shelh with rnani/ Valves, 



1. Chiton: Valves placed in tranverse plaits down the 



back. 



2. Lepas: Valves unequal; body sessile. 



5. Pholas: Shell bivalve, with accessory valves at the 

 hinge. 



