HERMIT CRABS. 145 



may well be replied, that he was specially destined to 

 keep the shelly Molluscs in check, as some enemies seem 

 provided to every animal, that the balance might be 

 preserved between the several species of the animal 

 kingdom. But, be this as it may, we find in the forma- 

 tion of the Pagurus his charter for acting as he does. 

 All the forepart of his body is coated with mail, like that 

 of other crabs, while his hind-parts are soft, and covered 

 with a membrane in which the mere rudiments of shelly 

 plates may be traced. The tail, however, is furnished 

 with a pair of hooks, by which it can lay hold of ob- 

 jects. The back-part of his body, indeed, so obviously 

 resembles that of one of the Spiral-shelled Molluscs, 

 that it requires but a glance to see that the cast-off 

 clothes of one will equally suit the other. And in early 

 life the Paguri are probably contented with nestling in 

 the deserted shells which may be found on the shore, 

 and to which they readily attach themselves by means 

 of the hooks of their tail, so that they can move about 

 with as great ease as if there was a regular organic 

 adhesion. But, as they advance in size, they require 

 larger houses ; the first-selected shells are therefore de- 

 serted, and new ones chosen. Sometimes the Pagurus 

 continues to select deserted shells. But, judging from 

 the freshness of the shell in which we find him, it is 

 probable that he more frequently attacks living speci- 

 mens, seizing the animal with his claws before it has 

 time to retreat ; and, having devoured its flesh, appro- 

 priates the shell. Mr. Bell* states that such is pro- 

 bably the fact, though he has not himself witnessed it. 



* "History of British Crustacea," p. 173. 



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