CRABS AND SHRIMPS. 
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the deeps. Others, which are more strictly oceanic, dis- 
play the same structure in a yet higher degree. 
It is impossible to walk along a beach by the edge of 
the tide without observing many univalve shells running 
to and fro, with an agility far greater than that of the 
sluggish mollusks, whose houses they originally were. On 
looking closely at them, we see the antenna:, eyes, and 
claws of what seems a minute Lobster projecting from 
each. If we take it up, the jealous little rogue withdraws 
into the house, pulling his legs after him, and claps one 
stout claw upon the other, in such a way as effectually to 
bar the intruder’s entrance. We may smash the shell upon 
a stone, and thus execute a forcible ejection (it is no more 
than he deserves, for the house is not his own, and he pays 
no rent), and then we sec that the hinder parts are 
curiously distorted and twisted, to fit it for tenanting a 
spiral shell. It is not a Lobster at all, but a H ermit-crab 
( Pagurus ), and this is the mode of life for which it is cre- 
ated. The abdomen is covered with a soft skin instead of 
a shelly crust, and therefore needs protection; and this 
is provided by the instinct which teaches the Crab to search 
for some empty univalve shell of suitable size, and to 
appropriate it for himself. Some laughable scenes occur 
when the old house becomes too strait for him to live any 
longer in it, and Iris growing bulk compels him to look out 
for a new lodging. Like a sound philosopher, he never 
loses grasp of the old shell till he has found a better. 
Tropical countries have many species of Crustacea, 
which, front their terrestrial habits, arc denominated Land- 
crabs. Those of the West Indies ( Gecarcinus ) make bur- 
rows in the soft earth, whence they wander by night for 
