CRUSTACEA. 
451 
THE CRAB. ( Cancer pagurus.) 
CRABS are of various sizes, some weighing several pounds, 
and others only a few grains, all of different species. 
They move not forward, but on one side, as it suits them 
best. They have a small tail closed on the body ; which 
is a considerable and essential difference between them 
and the lobsters, prawns, shrimps, and cray-fish. 
The most remarkable circumstance in the history of 
these animals, is the changing of their shells, and the 
renewal of their broken claws. The former, as it is 
stated, is done once a year, and usually between Christ- 
mas and Easter. During the operation they retire among 
the cavities of rocks, and under great stones. Crabs are 
naturally quarrelsome amongst themselves, and frequently 
have serious contests, by means of those formidable 
weapons, their great claws. With these they lay hold of 
their adversary's legs ; and wherever they seize, it is not 
easy to make them forego their hold. The animal seized 
has, therefore, no other alternative but to leave part of 
the leg behind in token of victory. 
An experiment was tried to prove the extremely tena- 
cious disposition of the Crab. By irritating it, a fisher- 
