SYNOPSES OF NORTH-AMERICAN 
INVERTEBRATES. 
XI. THE'CATOMETOPOUS OR GRAPSOID CRABS OF NORTH 
AMERICA. 
MARY J. RATHBUN. 
One of the most familiar forms of the Catometopa is the 
common ocypode, or sand crab, which lives on the beaches in 
abundance south of New England. It digs holes in the sand, 
occasionally retreating to the water when frightened. It is 
protected by its color, resembling that of the sand, and by the 
swiftness of its movements. 
The fiddlers, which may be recognized by the extraordinary 
development of one of the claws of the male, are represented 
by many species which burrow in sand beaches or in muddy 
banks of streams and ditches in the salt marshes, while at least 
one species, Uca minax, extends up rivers quite to fresh water. 
Of the Grapside, the Sesarma reticulatum also burrows in 
muddy banks. Its congener, S. cinereum, is sometimes known 
as the * wood crab," from its occurrence under logs and drift 
and about wharves, wood piles, etc. On the Pacific coast, the 
species of Hemigrapsus are abundant under stones and on mud 
flats in salt or brackish water. 
The common land crab of tropical America and the West 
Indies, Cardisoma guanhumi, occasionally makes its appearance 
in Texas. It is the only member of the Gecarcinida which 
comes within the limit of this paper. 
The Pinnotherida are readily known by their small .size, 
small eyes, often soft or membranaceous integument, and com- 
mensal habit, dwelling often in the shells of bivalve mollusks, 
in the tubes of annelids, or on sea-urchins. The best known 
species is the common oyster crab, Pinnotheres ostreum, which 
is often cooked and eaten with oysters. 
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