ASTERIOIDS. 



503 



known as Heart-Urchins. The Genera Spatangns, Bris- 

 sus, AmpJiidotns, and others belong here. Most of the 

 Spatangidas bury themselves in mud or sand. Brissus 

 is found on the coast of Florida. 



SUB-SECTION III. 



THE ORDER OF ASTERIOIDS, OR STAR-FISHES. 



THIS Order comprises echinoderms which are more or 

 less star-shaped, the disk or central portion gradually 

 merging into the rays, beneath which the locomotive 

 suckers extend the whole length ; and the calcareous 

 skeleton is composed of movable pieces, so that these ani- 

 mals can bend themselves in any direction. There is al- 



Fig. 488. 



rtt&*?f' 



iwv'v-r: 



^?w^;Y!O^r-j?^\''^'""" i .y^''~"< '''. A ''' '"' '-' '"'''-' 



apr-rT:-.,- ; !f J :. '. ,-' -V..-I' '.;C 'rn\'-';- , ' r. ^..^'Cr'- .' ' i--*-.'.! 



: '- -,!V^- '>'.->' fe'l^,^','- ^ rl; " - s^'T? r.i- : /'H' ' 



' - A; :^; M.'- >,?'%-^,-" s -- ;--^^ o;yy 



-r^-r^. ; - ; . i^^^^j^^^ 



^^ 



m 



aia 



Star-Fish, Astcracanthion. Coast of New England. 



most every possible form, from those which have the arms 

 long and graceful to those in which the arms and body 



