CHARACTERISTIC DEEP-SEA TYPES. SEA-URCHINS. 93 



be capable of very rapid movements, if they at all correspond to 

 those of their shallow-water allies. 



As it is brought to the surface Co3lopleurus is most brilliantly 

 colored, the test varying from a rich light chocolate in the inter- 

 ambulacra to the brilliant orange or yellow ambulacral areas. 



Fig. 358. Coelopleums floridanus 



The primary radioles vary greatly in color, from a delicate straw, 

 often nearly white, to a bright carmine or orange ; the base of 

 the spines being usually colored, and the shaft more or less ir- 

 regularly banded. 



