203 

 Genus. CHITON.* Plural, CUtones. 



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 in- 

 cumbent on that of the next ; they are surrounded 

 and connected by an elastic coriaceous membrane, 

 which allows of the free movement of the valves, 

 it is either scaly, hairy, or spinous. 



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 

 arrangment of its moveable valves united by a 

 coriaceous membrane. This latter substance is 

 capable of sufficient expansion and contraction 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. 

 Thus covered by its scales it lies like a pebble at 

 the bottom of the sea, and so contrives frequently 



* Plate X. figure 5. 



