24 ANIMAL PARASITES AND MESSMATES. 



very like miniature lobsters, which lodge in deserted 

 shells, and change their dwelling-place as they grow 

 larger. The young ones are content with very little 

 habitations. 



The shells which give them shelter are such as have 

 been shed, which they find at the bottom of the sea, and 

 and in which they conceal their weakness and their 

 misery. These animals have an abdomen too soft to 

 bear the dangers which they meet with in their warfare, 

 and that they may be less exposed to the claws of their 

 numerous enemies, they take shelter in a shell which 

 serves at the same time both as a dwelling and a buckler. 

 Armed cap-a-pie, the soldier-crabs march, boldly on the 

 the enemy, and know no danger, since they always have 

 a secure retreat. 



But this animal does not live alone in this asylum. 

 He is not so much of an anchorite as he appears to be, 

 for by his side an annelid usually instals himself as a 

 messmate, which forms with the Pagurus one of the 

 most terrible associations that are known. This. annelid 

 is a long worm, like all the nereids, whose supple and 

 undulating body is armed along its sides with arrows, 

 lances, pikes, and poniards, the wounds of which are 

 always dangerous. It is a living panoply which glides 

 furtively into the enemy's camp without giving the 

 alarm. 



"When a pagurus is on the march it resembles a nest 

 of pirates, who never cease their exploits till all has been 

 ravaged around them. This shell is so innocent in its 

 appearance, that it introduces itself everywhere without 

 provoking the least suspicion. It is usually covered with 

 a colony of Hydractinise, and in the interior, Peltogasters, 



