OPHIUROIDEA 



19: 



this genus. While Ophiochondrus is usually referred to the family 

 Hemieuryalidce or to a separate subfamily Oj^hiochowIrincB, 

 0. armatus, in the opinion of the present author, is a true 

 Ophiacanthid, 



1. Ophiochondrus armatus (Koehler). (Figs. 109-110.) 

 (Syn. Ophioplus armatus Koehler.) 



Scales of dorsal side small, rounded, not imbricating, each 

 carrj'ing a short spine. The radial shields also covered by such 

 scales, leaving only a small part at the 

 distal end free. Dorsal arm plates 

 divided into a larger outer part, with 

 strongly convex outer edge, and a smaller, 

 more or less rectangular, inner part. A 

 membranous space separates the dorsal 

 plates of each two consecutive joints 

 (Fig. 1 10, 2). The dorsal plates are thus 

 divided into two nearly to the end of 

 the arm. Ventral plates somewhat 

 broader without than mthin, with 

 straight outer and inner edge, also 

 separated from each other by a mem- 

 branous space. Tentacle pores very small, only the three proximal 

 pairs distinct. No tentacle scale present (on the specimens in 

 hand). Five to seven short, smooth, outstanding arm spines 



Fig. 109.— Ophiochondrus 

 armatus ; dorsal side. 

 Slightly enlarged. 



Fig. 110. — Ophiochondrus armatus-, part of oral side (1) and three arm 

 joints, dorsal side. x 9. 



of about equal length. Three (2-4) small mouth papillae on each 

 side of jaw. Mouth shields broader than long, with an obtuse 

 outer lobe. Adoral shields very broad, not prolonged outwards. 



