136 EXPLANATION OF THE PLATES. 



Fig. 9. Terminal knob of arm seen from above. 



Fig. 10. A terminal knob, seen from the actinal side. 



Fig. 11. The same, seen from the end. 



Fig. 12. Madreporic body. 



All Figures natural size, with the exception of Figs. 9-12, which are somewhat enlarged. 



The coloring of this species is quite dull; it has a grayish hue, with large square patches of brown arranged along the 

 margin of the arms. The color of the abactinal surface is frequently iu lines, one in central part of the arms, the others 

 along tlieir margin. The ambulacral tentacles are yellow. 



