ECHINODEBMA TASYSTEMA TIC HE VIE IF 



297 



Pcntaceros, Aiiqjhiaster, Calcita, Asterodiscus, etc. 

 nasteria, Tylastcr, Asteropsis, 

 Marginaster, etc. Fam. 8. As- 

 terinidse : Gmieria, Asterina, 

 PnJmipcs, etc. 



Older 2, Cryptozonia. 



Asteroidea, in which the mar- ,.- ; 

 ginal phites are indistinct and V- \ 

 more or less rudimentary in the ■*- - 

 adult. The supramarginal plates v 



are often separated from the in- 

 framarginal by intermediate plates. The 

 papulse are not limited to the apical sur- 

 face, but often occur also between the 

 marginal plates and on the oral (lowei) 



Fam. 7. Gymnasteriidae : Gym- 





— J 



"MV^rfsm^'py^, 



Fig. 241.— Cnemidaster Wyvillii (after Sladen). dc, Dor.soeentr;i 

 sm, supraiiiarginals ; d, dorsals ; t, terminals 



■, railials ; hn. basals 



surface of the body. Amljulacral plates narrow, closely crowded. Tiibe-feet'often 

 in four rows. In the oral skeleton the ambulacral or interamhulaeral ))]ates are 

 prominent. Pedicellari;ie sessile or pedunculate. 



