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-erab, Ocypoda arenaria. Often when pur- 
sued they will run into the surf instead of to their holes. The 
common edible crab, Cullinectes sapidus, of the Atlantic coast, the 
fiddler-crabs, and the spider-crabs are among the well-known 
representatives of Brachywra. 
FAMILY PORTUNIDE 
SWIMMING CRABS 
Genus Carcinides 
C. meenas (M. J. Rathbun), Carcinws meenas (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 anda 
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, 
Carcinides menas, 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 form swimming-paddles. It is a very lively creature and has 
reckless audacity when brought to bay, which justifies its specific name 
(which implies frenzy). The French call it crabe enragé. 
