424 



ZOOLOGY 



SECT. 



FIG. 342. Metacrinus interruptus, 

 (After P, H, Carpenter,) 



in an armour of close- 

 fitting plates ; but in 

 the vast majority the 

 body- wall is comparat- 

 ively soft, being strength- 

 ened merely by a great 

 number of minute os- 

 sicles of a variety 

 of shapes. In Synapta 

 (Apoda) numerous mi- 

 nute anchor-like spicules, 

 each connected with a 

 latticed plate, project 

 from the surface, and 

 cause the animal to ad- 

 here to soft bodies with 

 which it comes in con- 

 tact. Around the mouth 

 is a whorl of tentacles 

 pinnate, shield-shaped; or 

 arborescent. The tube- 

 feet are sometimes en- 

 tirely absent. When pre- 

 sent they are usually 

 uniform in character 

 throughout, and may be 

 arranged in five regular 

 longitudinal rows, or 

 scattered over the entire 

 surface. Sometimes, as 

 has already been stated 

 in the account of Colo- 

 chirus, the tube-feet of 

 the dorsal and even some 

 of those of the ventral 

 surface may assume the 

 form of papillae. In the 

 Elasipoda the tube-feet 

 of the dorsal surface 

 are remarkably modified, 

 taking the form of greatly 

 elongated processes. 



In the Crinoidea the 

 general shape is that 

 which has been described 

 in the case of the 

 Feather - star star - like, 

 with a central disc anc( 



