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 been 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. squamosus 
possessing only 7 valves with a perfect margin ; 
but these must be considered as hisus nature. 
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 Patellae, it is generally found parasitical, but 
possesses the power, of removing from its station. 
The name of the Genus, Chiton, is derived from 
the Greek word %/ro;v, signifying a coat of mail ; 
and aptly expresses the loricated appearance of 
the shell, arising from the position of the valves. 
