198 MULTIVALVES. 



GENUS. CHITON* 



COAT OF MAIL. 



Generic character. Shell multivalve, com- 

 posed of eight valves, rarely of seven or six ; 

 form convex, oval ; the valves are arranged in an 

 imbricated manner, the margin of one being 

 incumbent on that of the next ; they are sur- 

 rounded and connected by an elastic coriaceous 

 membrane, which is either scaly, hairy, or 

 spinous, and allows of the free movement of the 

 valves. 



OBSERVATIONS ON THE SHELL AND ITS 

 INHABITANT. 



The Chitons are readily distinguished from all 

 other testaceous mollusca by the form of their 

 shell, which very much resembles a small vessel 

 or boat turned upside down, and by the peculiar 

 arrangement of its moveable valves attached by 

 a coriaceous membrane. This latter substance 

 is capable of sufficient distension and contrac- 

 tion to admit of considerable play in the valves, 

 so that the animal can roll up its shell into the 

 form of a ball, having all the appearance of a 

 wood-louse. Contracted and covered by its 

 scales it lies like a pebble at the bottom of the 



* Plate X. figure 5. 



