SEA-STARS AND SEA-URCHINS. 95 



act of renunciation of limbs that offend, is but a prelude to 

 the extinction of vitality in the trunk. 



In the illustration here given of the Granulate Brittle-star, 

 it will be seen that the rays do not merge imperceptibly into 

 the trunk, but are attached to it by a kind of dovetail joint on 



GRANULATE BRITTLE-STAR. 



the upper side. Below, the arms, at their termination, form a 

 ring, within which is the mouth, whilst the trunk acts as a 

 roof above the mouth, and overhanging all round. The rays 

 are composed of a series of joints, which allow free lateral 

 action, or wriggling, but not much vertically. Each of these 



G 



