212 



LIFE, IN ITS INTERMEDIATE FORMS. 



material for future legs as required. " When the limb is 

 thrown off, the blood-vessels and nerve retract, thus leav- 

 ing a small cavity in the new-made surface. It is from 

 this cavity that the germ of the future leg springs. A 

 scar forms over the raw surface caused by the separation, 

 which afterwards forms a sheath for the young leg." " As 

 the growth advances, the shape of the new member be- 

 comes apparent, and constrictions appear, indicating the 

 position of the articulation ; but the whole remains unpro- 

 tected by any hard covering until the next change of 

 shell, after which it appears in a proper case, being, how- 

 ever, still considerably smaller than the corresponding 

 claw on the opposite side of the body, although equally 

 perfect in all its parts." * 



* Jones's " General Outline," p. 343, 



