OPHIUROIDEA 



251 



2. Ophiopleura aurantiaca (Verrill). (Fig. 137.) 



(Syn. Ophioglypha, Ophiura aurantiaca Verrill.) 



Scales of disk very small and indistinct ; primary plates 

 usually not distinguishable. Radial shields small, rounded, 

 widely separate, forming only short ridges beneath the scaling, 

 and usually these ridges are not distinct. Notch above arms 



Fia. 137. — Ophiopleura aurantiaca ; part of dorsal and ventral side, x ea. 6. 

 (After Farran, Deep-water Ast. . . . Ireland ; slightly altered.) 



inconspicuous, with 1-3 rudimentary dorsal plates. Arms not 

 roof-shaped, not flattened below. Dorsal plates about as long 

 as broad, rounded quadrangular. At base of arm there is a 

 fairly conspicuous naked part between the dorsal and the lateral 

 plates. Ventral plates with convex outer edge, sometimes with 

 a median prominence, the proximal ones in contact. Pores 

 small, excepting the second pair. The third pair with 3-4 small 

 papillae, the following ones with 2 and then soon only 1. Arm 

 spines 3 ; the upper one about as long as an arm joint, flattened. 



