STAR-FISH AND SEA-URCHINS. 



269 



it may very likely attach its uppermost rays to it, 

 and then, letting go its other attachments, swing 

 from the one support to the other. The activity 

 and co-ordination manifested in these acrobatic 

 movements are surprising, and give to the animal 

 an almost intelligent appearance. 



In Astropecten the ambulacral feet have become 

 partly rudnnentary, inasmuch as they have lost 



Fig. 43.— Natural movements of a Star-fieh on reaching the surface of water. 



their terminal suckers (Fig. 44). These Star-fish, 

 therefore, assist themselves in locomotion by the 

 muscular movements of their rpys, while they use 

 their suckeiiess feet to run along the ground some- 

 what after the manner of centipedes. It is to be 

 noticed, however, that altliough the feet have lost 

 their suckers, the Star-hsh is still able to make them 

 adhere io solid surfaces in a comparatively inefficient 



