240 BULLETIN OF THE 



narrow and tapering within, where they join. First under arm-plate as broad 

 as long, four-sided with much rounded corners. Those beyond have essentially 

 a five-sided outline, but the second plate has its corners much rounded, while 

 the others are more regular and have a well-marked peak within. Side arm- 

 plates meeting below, but not above next the disk; slightly flaring so as to 

 make a distinct shoulder, which carries the spines. Upper arm-plates Iroad 

 wedge-shape, with an angle inward, which in the ilrst two is truncated. 

 Upi)er surface of disk with a central rosette of six slightly swollen, irregularly 

 rounded primary plates, outside which is the great plate which separates the 

 ends of the radial shields, and, in the interbrachial space, two other large 

 plates, one of which is on the margin. Besides these there are numerous 

 small intercalated scales. Interbrachial spaces below covered by half a dozen 

 irregular angular plates ; besides which tlie narrow genital plates appear run- 

 ning along the genital openings quite to the margin of the disk. A row of 

 fine papillaj stands on the edge of the genital scale, which grow suddenly 

 larger, as the plate passes to the top of the arm, and form a close comb of flat- 

 tened papillae with rounded ends. Three small, equal, peg-like, spaced arm- 

 spines, less than half as long as a joint. Mouth-tentacles with five or six 

 minute, bead-like scales on each side ; the next have three or four ; the sec- 

 ond and third have three on the side arm-plates, and the fourth, one. Color in 

 alcohol, pale gray. 



Station 269, off St. Vincent, 124 fathoms, 4 specimens. 



This species stands nearest 0. costata, but has longer arm-spines, disk-scales 

 more swollen and separated, side arm-plates more flaiing, and radial shields 

 joined. 



Ophioglypha aurantiaca Vll. 



Vll., Amer. Journ. Sci., XXIIL p. 141, 1882. 



Plate IV. Figs. 34-36. 



Special Marks. — Disk covered by a smooth skin, through which the scales 

 of the upper surface are scarcely to be made out, while those of the lower 

 surface are more distinct. Three wide, flattened arm-spines, the upper one 

 longer than an arm-joint, the others not so long. No comb above the base of 

 the arm. 



Description of an Individual (Station 312). — Diameter of disk 11.5 mm. 

 Width of arm close to disk 2.5 mm. About eleven small, bead-like, slightly 

 spaced mouth-papillai to each angle. Four or five small spear-head-shaped 

 teeth. Mouth-shield very wide heart-shaped, with an obtuse angle inward ; 

 length to breadth, 2:1. Side mouth-shields long, with an irregular outline, 

 and widest at their outer ends. First under arm-plate rounded hexagonal, 

 and about as broad as long. The next two are of an irregular transverse 

 oval shape, and those immediately beyond are much wider than long with a 

 curve without and a peak within. Side arm-plates clinging close to the arm, 



