92 ANIMAL BIOLOGY 



danger, the males holding up their large claws in a threat- 

 ening manner while beating a lively retreat. 



FIG. 76. Pagurus bernhardus, hermit crab. (From Emerton.) 



The spider crabs, on the other hand, are generally very 

 sluggish in their movements. They usually have long, 



FIG. 77. A crab, Panopeus chilensis. (After M. J. Rathbun.) 



slender legs and a body narrowed and pointed in front. 

 In some species the back is covered with a growth of 



