OPHIUROIDEA OF THE BAHAMA EXPEDITION. 59 



scales visible, not very large, of nearly uniform size, most of 

 them bear a single, rather long tapered spine or shorter, 

 acute, very thorny spinule. The central scales bear the 

 shortest spinules, while the length increases toward the mar- 

 gin of the disk. Radial shields large, broad, irregular or 

 roundish, partly naked, slightly bilobed distally. The under 

 side of the disk is covered with flat, imbricated, subequal 

 scales, bearing a few small, conical spines. The radial 

 shields are partly separated by a narrow row of small scales, 

 bearing short, conical, thorny spinules, similar to those on 

 the central part of the disk; a few similar spinules arise di- 

 rectly from the radial shields. The interradial margins, in 

 one dry specimen, were rather deeply emarginate; in another, 

 equally dry, they were strongly convex. 



The oral shields are small, broadly pelecoidal, wider than 

 long, with the distal end evenly rounded, and the inner mar- 

 gins strongly incurved, and forming an acute proximal angle. 

 The madreporic shield is much larger and more rounded (pi. 

 V, fig. iff). The adoral shields are very large and broad, 

 rounded distally, with the adjacent edges joined extensively, 

 along the median line. The mouth-papillae and tooth-papillae 

 together, are about twelve to fifteen on each side of a jaw; 

 they are nearly equal, large, spiniform, acute. Those along 

 the distal part of the jaw may form two crowded rows; the 

 tooth-papillae form a crowded cluster of four or five or more 

 at the tip; five or six, or more, serving as oral tentacle-scales, 

 form a close distal cluster. 



First under arm-plate small, concave, with a pair of pro- 

 cesses on the inner angles. Under arm-plates, except on the 

 basal joints, broadly triangular, with the distal side broadly 

 rounded and slightly emarginate in the middle; lateral angles 

 very prominent; inner margins nearly straight, forming a 

 sharp median angle. The lateral plates meet along the 

 median line and separate both the dorsal and ventral plates, 

 more or less. 



Tentacle-scales two on one or two basal joints; one of 



