OPHIUROIDEA OF THE BAHAMA EXPEDITION. 1 >j 



triangular, and then disappear. Two very small, conical, sub- 

 equal arm-spines are present on the proximal joints; they de- 

 crease rapidly in size farther out, and soon become abortive. 



Diameter of disk 9 mm.; the longest broken stump of an 

 arm is 17 mm. long; this has sixteen joints. 



Off Havana, no to 260 fathoms, four examples. 



This species is allied to O. acuferum, but differs in having 

 smaller dorsal arm-plates; only two arm-spines; smaller radial 

 shields; more numerous central disk-plates; more strongly bi- 

 lobed marginal plates. In one instance one of the latter 

 plates is broken up into four or five parts, probably due to 

 the repair of an injury. 



Ophioconis miliaria Lyman. 



Ophioconis miliaria Eyman, Bull. Mus. Comp. Zool., V, p. 221, pi. 

 Ill, figs. 49-51, 1878; Voy. Chall. pp. 106, 109, pi. XXXIX, figs. 7-9, . 

 (structure); Three Cruises of the Blake, II, p. 112, fig. 395, 1888. 



The single specimen obtained is somewhat smaller than 

 Lyman's type and differs in some respects from his figures, 

 especially in having shorter spines, longer tentacle-scales and 

 narrower under arm-plates. It is probably the same species, 

 however. 



Disk covered everywhere, above and below, with minute 

 rounded granules, which conceal minute, round, thin scales. 

 Arm-spines 5 to 7, long, slender, acute, flattened, partially 

 translucent, finely serrulate; the two upper are longer than 

 the rest, rather longer than two arm-joints; the lowest two 

 are shortest and most slender. Tentacle-scales two, nearly 

 equal, elongated, flattened, blunt, more than half as long as 

 the under arm-plates. Upper arm-plates in contact, strongly 

 arched, top -shaped, the outer end convex, the sides a little in- 

 curved. Under arm-plates shield-shaped, longer than broad, 

 with the sides incurved, the outer end rounded, the inner end 

 angulated. 



Diameter of disk, 6 mm. 

 v— 1 B 



