160 CYCLOBRANCHIATA.—CHITONIDZ. 
GENUS CHITON. 
The character which distinguishes the chitons 
proper from the Oscabrelles (Chitonellus), is that 
the dorsal plates of shell are comparatively large, 
much wider transversely than longitudinally, and 
all in contact with, and overlapping each other. 
This genus includes a large number of species, 
which are scattered over all seas, except in the 
very rocky shore, in greater or less abundance, 
fast adhering by the broad foot, exactly in the 
manner of limpets. The largest species are found 
on the tropical coasts of America, where some 
attain the gigantic dimensions of four, five, and 
even six inches in length. The Chiton spiniferus 
of Chili is said to reach the size last mentioned. 
The shells are much prized by conchologists, and 
they are consequently sought by collectors in fo- 
reign countries, though the operation is sometimes 
attended with danger. I have myself collected 
some kinds, of large size, on the shores of Jamaica, 
among sharp and rugged rocks, where the surf 
dashing in breaks over the naturalist at almost 
every wave, drenching him, of course, and often 
buffeting him against the rocks, and washing his 
rize from his hands the very moment he has 
Actuched it from its hold. 
The mode in which Chitons are procured re- 
quires some skill and practice, as if they are 
touched without being detached in an instant, they 
increase their adhesion so greatly as to defy all 
efforts to remove them without lacerating the 
edges of the mouth, and thus spoiling them as 
cabinet-specimens. An old knife, that has the tip 
