142 



zooLoav 



because the carapace is arched in front. The carapace is also 



broader than long, and narrower behind than in front. The 



legs of this family are short and 

 broad, and in some species the pos- 

 terior pair is especially broad — an 

 adaptation for swimming. These 

 oralis may be divided into two 

 groups — the burrowing crabs and 

 swimming craljs. To the burrowing 

 crabs belongs the genus Cancer 

 (Figs. 137, 138), which includes the 

 edible crab of Europe, especially 



prized in England, together with several American species; 



while our common edible, soft-shelled or blue crab, Callinec'tes 



Fig. 1.37. — Panopeus sayi, al- 

 lied to Cancer. The niufl- 

 crab. One-half nat. size 

 Photo, bv W. H. C. P. 



Fig. 1.38. — Cancer irroratus, the rock-crab. Reduced to one-third. Photo. 

 by W. H. C. P. 



hasta'tus of the East, and the beautiful " lady-crab " (Fig. 139) , 

 belong to the swimming group. Crabs of other families are, 



