13-1 BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



Spicules and plates of what is probably the primitive type persist in many of the 

 holothurians, and are developed in certain situations in species of all the other 

 classes, in the crinoids mailing up the visceral, and most of the perisomic, skeleton. 



Flo. 81.— Dorsal view of the centkal structures and of a single post-radlal series of a sPEaMEN of comanthcs 



SOLASTER FROM SOUTHERN JAPAN, SUO>VlNQ THE RELATIVE PROPORTIONS OF THE VARIOUS PARTS. 



These spicules are in general suggestive of the spicules of certain sponges and 

 alcyonarians, both in form and in origin, and it is in tiie skeletons of those animals 

 that the skeleton of the ccliinodcrms, though entirely independent in origin, finds 

 its nearest counterpart. 



