172 



HALF AN HOUR WITH SEA-URCHINS 



means of its long arms. Mr. Fred. Kitton, of 

 Norwich, has, we think, thrown some light on the 

 means by which these animals are able to use their 

 arms as means of locomotion, in a paper contributed 

 to Hardwicke's " Science Gossip " in September, 1866. 



Fig. 91. 



("laws from Ophiocoma rosula, X 150. 



He found that whilst examining th remains of an 

 arm of 0. rosula, after maceration in caustic potash, 

 a number of claw-shaped bodies, like those shown in 

 Fig. 91, presented themselves. These claws had 

 not previously been noticed by any naturalist. By 



