CRINOIDEA. 



453 



arms dividing and subdividing until the branches are said 

 to number more than 80,000 1 



FIG. 684. 



SUB-SECTION VI. 

 THE ORDER OF CRINOIDEA OR CRINOIDS. 



THE echinoderms of this order are called Crinoids on 



account of the plant-like or lily-like appearance of many 



of the species, especially of 

 those found fossil in the 

 rocks. The name Crinoid 

 is from brinon, a lily, and 

 eidos, like. 



In the Crinoids we see 

 a great development of the 

 aboral region as compared 

 with the oral ; and the for- 

 mer is generally calyx-like, 

 and composed of immovable 

 plates, and in many cases 

 the whole supported on a 

 long flexible stem composed 

 of many plates of a beauti- 

 ful structure. 



Some kinds of Crinoids, 

 as the Rosy Feather-star or 

 Comatula, have a stem in 

 the young state, but at length 



drop from the stem and spend the remainder of their 



life as free crinoids. 



There are but a few living species of Crinoids. But in 



the rocks, in various parts of the United States and in 



Crinoid, Pentacrinus caput-medusce. 

 West Indies. 



