THE MAILED WARRIORS OF THE SEA. 171 
ment and consider how many thousands of hermit- 
crabs of all sizes feed on the dead fish and garbage 
of every sea-shore ; and how well they are protected 
by the strong winkle and whelk shells which they 
choose for their houses, so that they can hold their 
own, when the tiny crabs wearing only their own 
brittle coats, would soon be cracked and eaten. 
Evidently the hermit-crab has found stolen houses 
an advantage to him, and the way in which his tail 
has become adapted to his home, while keeping all 
the usual parts of a crab, is most curious. 
One of his claws (c, i) is much bigger than the 
other, and closes the opening of the shell after the 
rest of the body is drawn in, thus barring the door 
against most intruders, although the fiddler-crab 
sometimes manages to thrust in his thin pincers and 
pinch the hermit to death. His next two feet are 
strong, though pointed, and are able to take a firm 
hold on the sand as he walks and to bear the weight 
of the shell, while the two comparatively thin pairs 
which follow serve to shift his body in its house. His 
swimmerets, no longer needed, are stunted and small, 
and his soft abdomen follows the winding of the shell 
in which he lives ; while the tail fin, no longer broad 
and flat, is turned into a kind of grappling hook (/z), 
which takes hold so firmly that he is scarcely ever 
dragged out alive. So there is but little danger for 
him except when he is changing his shell for a larger 
one, and this he does wonderfully quickly, never 
leaving his old house till he has found a new one. 
In fact the hermit succeeds so well in life that he is 
extremely pugnacious, and will soon make great 
havoc in an aquarium. Moreover, he often feeds two 
