SECT. vii. DECAPOD CRUSTACEA. 197 



eye-stalks bent to the right and left. It requires several 

 moults to bring this creature to its final size and 

 form. 2 



Crabs sometimes die while moulting, and occasionally 

 are unable to extricate a limb from its shell, and conse- 

 quently lose it. But if a limb be fractured they can cast 

 it off at the second joint, and soon after a diminutive 

 limb is formed, which attains its fall size at the next 

 moult ; but if the crab has not strength enough to cast 

 it off, it bleeds to death. 



Anom.ura. 



The Anomura is a family of Decapods intermediate 

 between the long and short- tailed Crustacea. There are 

 nine or ten genera and many species, chiefly distin- 

 guished by the development of the head and thorax, 

 and the softness of a non-locomotive tail : of these 

 Pagurus, or Hermit crab, is assumed as the type or 

 representative. 



The carapace is long and convex, scarcely extending 

 over the basal joints of the feet. The claw feet are 

 short, with a very broad hand and sharp pincers ; but 

 the Hermit crab and some of its congeners are irregu- 

 larly formed ; for the last pair of walking feet, instead 

 of being attached to the thorax, like the others, are 

 fixed to the first part of the tail, are generally folded 

 over the back, and are employed to sweep foreign 

 matter out of the gills. The mouth and its masti- 

 cating organs are similar to those in the crab, except the 

 exterior pair of foot-jaws, which are longer and move 

 like feet. But that which distinguishes the Pagurus 

 and its fellows from every other Decapod is the softness 

 of its unsymmetrical tail, all the appendages of which 

 are abortive, and the extremity, instead of ending in a 



2 Mr. C. Spence Bate. 



