viir 



ECHINODERMA TA SYSTEM A TIC RE TIE W 



29' 



Pentaccros, Aniphiaster, Culcita, Astcrodiscus, etc. Fam. 7. Gymnasteriidse : 

 nastcria, Tyla.stcr, Asteropsis, 

 Marginaster, etc. Fam. 8. As 

 terinidse : Ganeria, Asterina, 

 l'ni ni Ipi-s, etc. 



Order 2. Cryptozonia. 



Asteroidea, in which the mar- 

 ginal plates are indistinct and 

 more or less rudimentary in the 

 adult. The supramarginal plates 

 are often separated from the in- 

 framarginal by intermediate plates. The 

 papulae are not limited to the apical sur- 

 face, but often occur also between the 

 marginal plates and on the oral (lower) 





FIG. '240. Anthenea tuberculosa, Gray? 

 juv. (after Sladen). 1, Snpramarginal plates ; 

 '2, pedicellarise ; 3, madreporite ; 4, anus. 



FIG. 241. Cnemidaster Wyvillii (after Sladen). dc, Dorsocentral ; /, radials ; bn, basals ; 

 sm, supramarginals ; d, dorsals ; t, terminals. 



surface of the body. Ambulacral plates narrow, closely crowded. Tube-feet often 

 in four rows. In the oral skeleton the ambulacral or interambulacral plates are 

 prominent. Pedicellarife sessile or pedunculate. 



