42 CHITON. 



By far the greater number of species consist of 

 8 valves ; and the specimens of 6 or 7 are so rare, 

 that they may, not unreasonably, be suspected of 

 having sometimes heen either carelessly or fraudu- 

 lently composed of disconnected valves. The mar- 

 ginal membrane being entire, will always afford an 

 obvious security against such sort of imposition. 

 There are, however, instances of the C. sqiiamosus 

 possessing only 7 valves, with a jjcrfect margin ; 

 but these must be considered as lu.ms naturce. 



The animal adheres, usually, to rocks, or other 

 shells, by means of a gelatinous fluid which exudes 

 from the papillary under-surface of its body. Like 

 the Patella*, it is gencrallv found parasitical, but 

 possesses the power, of removing from its station. 



The name of the Genus, Chiton, is derived from 

 the Greek word x^tmv, signifying a coat of mail ; 

 and aptly expresses the loricated appearance of 

 the shell, arising from the position of the valves. 



