64 



ECHINODEEMATA. 



origins beneath by large shield-shaped plates : 

 cirri (or flexible threads between the ray-spines) 

 simple. 



0. texturata. 



albida. Fig. 94 ; n. s. 



OpMocoma (Agassiz). Rays simple, scaly, not 

 prolonged into the disk above ; and separated at 

 their origins beneath by small five-sided plates: 

 cirri pinnate. 



0. neglecta. 

 punctata. 



O. filiformis. 



0. bellis. 0. Ballii. 



brachiata. Goodsiri. 



parmularia. 



