FEATURE IN DEEP-SEA OPHIURANS. 11 



" Challenger," Station 214, N. E. of Celebes ; 500 fathoms ; 1 specimen. 

 This species stands nearest 0. ciispidata, from which it differs in the scaling of the 

 disk, and by having two tentacle-scales. 



Ophiambix-' gen. nov. 



Disk flat ; arms wide and flat ; and both beset above with sharp grains, or spines. No 

 radial shields or upper arm-plates externally visible. Small, sharp, mouth-papillae and 

 teeth ; no tooth-papillae. Tentacle-poree very large. Side arm-plates widely separated 

 above and below, but occupying a considerable part of under surface of arm. Arm-spines 

 translucent, hollow, and with an uneven surface. 



Ophiambix aculeatus sp. nov. Plate II, figs. 29-31. 



Special marks. On upper side of disk and arms, sharp grains, which increase to short 

 spines on margin. Interbrachial spaces below delicately scaled. Three sharp arm-spines. 



Description of an individual. Diameter of disk 5 m.m. Width of arm without 

 spines, 1.5 m.m. The rather small jaws, which are separated at their outer ends, bear 

 each, three or four small, sharp, translucent papillae, while the apex is occupied by the 

 lowest tooth, which is peg-shaped and much larger than the papillae. Mouth-shields very 

 small, of a transverse oval shape, with a slight peak within. Side mouth-shields short and 

 small, tapering at each end, and wedged between outer ends of jaws. First under arm- 

 plate nearly as large as those beyond, somewhat longer than broad, bounded within by 

 an obtuse angle, without by a gentle curve, and, on the lateral sides, by reentering curves. 

 Length to breadth of 4th plate, 0.6: 0.5. The wide space on either side of the under arm- 

 plates is occupied partly by the very large tentacle-sockets, and partly by the side arm- 

 plates which make narrow purtitions between the tentacles, and then enlarge into a strong 

 but very low spine-crest. Upper surface of arm covered by skin, and evenly set with 

 sharp, conical grains, about eight in the length of 1 m.m. Disk much flattened, and 

 somewhat puffed in the interbrachial spaces ; evenly set above with sharp conical grains, 

 which are similar to those of the arm, and which are continued as minute conical spines, 

 over the margin. Interbrachial spaces below destitute of spines and covered by a thin, 

 delicate scaling. No radial-shields are externally visible. Genital openings large, extend- 

 ing from outer corner of mouth-shield to margin of disk. The extremely flattened arm 

 bears, on either side, three translucent, hollow, slightly flattened, sharp, tapering arm- 

 spines, whereof the two upper are as long as two joints, and the lowest about two-thirds 

 as long. Three or four short, sharp, spine-like tentacle-scales, standing on the margin of 

 the very large pores, from which protrude simple club-ended tentacles. 



Color in alcohol, straw. 



" Challenger," Station 175, near Fiji Islands; 1350 fathoms; 1 specimen. 



^ 'Oi/Kr, a snake; d/(/3if, a cup. 



