OX CRUSTACEA. 
275 
brachyuri are rather runners than swimmers, and suffer 
themselves to proceed at the will of the waves, assisting them- 
selves in a trifling degree with their feet, t hey usually walk 
sideways, or backwards, and run with a velocity equalling 
or surpassing that of a horse, gaining, on the slightest ap- 
pearance of danger, their habitual retreats, or any which 
chance may happen to present. They pinch strongly with 
their claws or forceps, and sometimes sacrifice tnem by lea"\ - 
ing them within the hands of the person by whom they have 
been seized, that they may themselves escape. Nature re- 
pairs this loss the more speedily, if the breach be made at 
the joints, especially the second or third. 
The growth of the craw-fish is slow, and according to the 
testimony of fishermen, it is hardly saleable at the end of 
seven or eight years from its birth. Some Crustacea, such as 
those which remain habitually at great depths, in inaccessible 
situations, and which are better protected by the nature of 
their testa, may attain to a very considerable age. It was 
believed, in the time of Pliny, that some species could live 
for a period exceeding the duration of the life of man. M. 
Latreille has seen a great lobster (pnUnurus) of nearly six 
feet in length from one extremity of the body to the other, 
whence we may infer its great age. 
The family of Brachyurous decapods is composed of the 
genus Cancer or Crab. Under this name are commonly 
designated all the Crustacea analogous to craw-fish, and 
lobsters, but whose body is proportionally shorter and 
broader, with a small tail refolded on the breast. In the 
method of Linnaeus, the genus cancer has an acceptation 
much more general, since it comprehends the first three orders 
of Crustacea, and even a part of the fourth. 
The crabs remain in preference on coasts where there are 
rocks, in clefts where they are sheltered from the waves of 
the sea, and secured from the pursuit of their enemies. 
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