38 THE NATURAL HISTORY OP THE COMMON CRAYFISH. 



the limb, which remains in the hand of the captor, while 

 the crayfish escapes. This voluntary amputation is always 

 effected at the same place ; namely, where the limb is 

 slenderest, just beyond the articulation which unites the 

 basal joint with the next. The other limbs also readily 

 part at the joints ; and it is very common to meet with 

 crayfish which have undergone such mutilation. But 

 the injury thus inflicted is not permanent, as these 

 animals possess the power of reproducing lost parts to 

 a marvellous extent, whether the loss has been inflicted 

 by artificial amputation, or voluntarily. 



Crayfishes, like all the Crustacea, bleed very freely when 

 wounded ; and if one of the large joints of a leg is cut 

 through, or if the animal's body is injured, it is very likely 

 to die rapidly from the ensuing haemorrhage. A cray- 

 fish thus wounded, however, commonly throws off the 

 limb at the next articulation, where the cavity of the 

 limb is less patent, and its sides more readily fall 

 together ; and, as we have seen, the pincers are usually 

 cast off at their narrowest point. When such amputation 

 has taken place, a crust, probably formed of coagulated 

 blood, rapidly forms over the surface of the stump ; and, 

 eventually, it becomes covered with a cuticle. Beneath 

 this, after a time, a sort of bud grows out from the 

 centre of the surface of the stump, and gradually takes 

 on the form of as much of the limb as has been removed. 

 At the next ecdysis, the covering cuticle is thrown off 

 along with the rest of the exoskeleton ; while the rudi- 



