262 WEST AMERICAN SHELES 
Others cannot run, but in sheer helplessness wait 
for your kind decision to do them no harm, and 
their very inertness appeals to your sympathies. 
While the saucy crabs waste no time in ceremonies, 
and the sea-worms creep away as fast as possible, 
the poor mollusks can only cling to the rock for 
protection, or curl themselves into the smallest 
space and the most secure condition which their 
instinet can dictate. 
When you visit the seaside you will want to 
examine all these harmless little inhabitants of the 
ocean, and among them you will probably find 
some specimens of our next group of mollusks, 
the Chitons. The anatomy of these animals is 
similar to that of the Limpets, but they seem less 
highly developed, are more sluggish, and com- 
monly live under stones, away from all scenes of 
activity. 
But the peculiar feature that distinguishes them 
is the fact that the shell of the Chiton consists of 
eight parts, instead of a single shield. These 
parts, or valves, run across the body and overlap 
one another, like shingles on a roof. They are 
highest in the center, and they end in a leathern 
mantle which runs around the body, and which is 
highly contractile. This being the case, the Chiton 
shells cannot be preserved with the same ease as 
those of the Limpets, for the mantle must be dried 
while the valves are in their natural position. 
Probably the best way to prepare fine specimens 
is to bind the living animal upon a piece of lath, 
as it rests expanded in a pan of sea-water. It 
