42 



NATURAL HISTORY. 



joined to the stalk arose a circle of tentacles. When full grown it left 



its stalk and swam freely, pausing occasionally apparently to rest, and 



at such times the ten- 

 tacles came into play 

 as clasping organs, 

 holding the star firm- 

 ly to any object in the 

 manner shown in the 

 figure. 



The starfishes (Aste- 

 roids) are much more 

 numerous than the 

 crinoids. They abound 

 in all the seas from 

 low water-mark down 

 to two thousand fath- 

 oms or more. They 

 all consist of a central 

 disc, from which radi- 

 ate five or more arms. 

 In the group of brittle- 

 stars this disc is better 

 marked, and the arms 

 are longer, more slen- 

 der, and more easily 

 moved than in the 

 true starfish. These 

 arms are very brittle, 

 and frequently on tak- 

 ing these animals from 

 the dredge they will 

 all tumble to pieces, 

 apparently at times 

 from sheer spite, and 

 the late Edward Forbes 

 claimed that one fine 

 specimen which broke 

 all up in his hands 

 actually winked its 



eye in derision as it went down to the depths from which it came! 



These long arms are capable of considerable motion, and motion of such 



Fig. 43. 



■A free-swimming crinoid (Comatula), attached to the tube 

 of a worm. 



