308 CRUSTACEA. 



have such power in large individuals, that they have been seen to 

 seize a Goat, and drag it from the shore: They usually inhabit wa- 

 ter, but do not instantly perish when deprived of it; some species 

 even pass a part of their lives on land. Even they are compelled to 

 fix their domicil, either in burrows, or in cool, damp places. The 

 Decapoda are voracious and carnivorous. Certain species even pe- 

 netrate into cemeteries, and devour the dead. Their limbs are 

 regenerated with surprising promptitude, but it is requsite that the 

 fracture be at the junction of the articulations, and when accident 

 determines it otherwise, they know how to apply a remedy. When 

 they wish to change their skin, they seek a retired and solitary spot, 

 in order to be sheltered from their enemies, and to remain at rest. 

 When the change is effected, their body is soft, and has a more ex- 

 quisite flavour. A chemical analysis of the old shell proves it to 

 be formed of the carbonate and phosphate of lime, united in differ- 

 ent proportions with gelatine. 



FAMILY I. 

 BRACHYURA(l). 



Tail shorter than the trunk, without appendages or fins at the ex- 

 tremity, and doubled under in a state of rest, when it is received in 

 a fossula on the chest. Triangular in the males, and only furnish- 

 ed at base with four or two appendages, in the form of horns, the 

 superior of which are the largest, it becomes widened, and convex 

 in the females, presenting beneath four pairs of double hairy fila- 

 ments, destined to support the ova, and analogous to the sub-caudal 

 natatory feet of the Macroura, and others. 



This family may constitute but one genus, that of 



Cancer, Lin. 

 Or the Crabs. Naturalists, however, have now divided them into the Swim- 

 mers, Arcuated, Quadrilateral, Orbicular, Triangular, &c. differing in shape, 

 the number and form cf the spines or teeth, the relative proportion of the 

 eyes and their pedicles, &c. Each of these sections are again divided into 

 numerous genera. 



Among the most noted of these we find the Land Crabs of intertropical 



(1) Short-tailed. 



