274 



MARINE INVERTEBRATES 



of one side to pull with and those of the other side to push with. 

 As all the legs do not move at the same time, a continuous and 

 uniform motion is kept up. Some species move with great rapid- 

 ity, notably the sand-crab, Ocypoda arenaria. Often when pur- 

 sued they will run into the surf instead of to their holes. The 

 common edible crab, Cattinectes sapidus, of the Atlantic coast, the 

 fiddler-crabs, and the spider-crabs are among the well-known 

 representatives of Brachyura. 



FAMILY PORTUNIDJE 



SWIMMING CRABS 



GENUS Carcinides 



C. mcenas (M. J. Rathbun), Cardnus mcenas (Leach), the green 

 crab. This is one of the most common species on the Atlantic coast from 

 Cape Cod to New Jersey, and is very abundant in Vineyard Sound, Buz- 

 zard's Bay, and Long Island Sound. It is found between tide-marks, fre- 

 quently well up on the beach, hiding under loose stones ? also in tide-pools 

 and in holes and cavernous places on the shore. It is from one and a 

 half to two inches long, and a little more in breadth. It has five acute 

 teeth on each side of the anterior part of the carapace. Its color is green, 



Carcinidfs mienas, the green crab. 



spotted with yellow, making it quite conspicuous. The surface of the 

 carapace and limbs is more or less granulated. The posterior feet are 

 flattened to fonn swimming-paddles. It is a very lively creature and has 

 reckless audacity when brought to bay, which justifies its specific naiix 

 (which implies frenzy). The French call it crabe enrage. 



