Clark. — Ophiuroidea. 



PLA.TE 1. 



Figs. 1, 2. — Asteroschema monobactrum H. L. Clark. X 3. 



1. Upper surface. 



2. Lower surface. 



Figs. 3, 4. — Ophiacantha quadrispina H. L. Clark. X 2. 



3. Upper surface, to show upper arm-plates. 



4. Lower surface, to show mouth-parts, etc. 



