STRUCTURE OF THE HERMIT CRAB. 361 



appropriate its vacant residence, affording thus a 

 striking illustration of 



" The short, the simple plan, 

 That they shall take who have the power, 

 And they shall keep who can." 



When feeding or walking about, the head and 

 thorax of the Hermit Crab project beyond the mouth 

 of the shell; but when they are alarmed, they draw 

 themselves in, closing the aperture of their domicile 

 with one of their claws, which is much larger than the 

 other. They hold on so firmly to their retreat, that 

 they will rather be torn asunder than quit their attach- 

 ment ; nevertheless, as they increase in size, they are 

 obliged to change their habitation for a more commo- 

 dious one, and the way in which they do this is very 

 amusing. They may, on such occasions, be fre- 

 quently observed crawling along a line of empty 

 shells left by the last wave ; and, as if unwilling to 

 part with their old domicile till a new one has been 

 obtained, they slip their tails out of the old house into 

 the new one, speedily again betaking themselves to 

 the former, if the latter is not found suitable. In 

 this manner they not unfrequently try a great number 

 of shells before they find one to their liking, and 

 combat fiercely for the possession of a promising 

 lodging. 



It will readily be supposed that, in order to adapt 

 these shell-frequenting anchorites to occupy a domicile 

 so foreign to the usual habits of their class, corre- 

 sponding modifications in the structure of the animals 

 will be rendered necessary; accordingly the pecu- 



