MUSEUM OF COiMrAU.VTlVE ZOOLOGY. 131 



space are two regular transverse rows of long and narrow plates. Genital 

 scales small, niucii longer than wide, extending from the outer corners of the 

 mouth-shield to the disk margin. On the margin of the disk there is a fringe- 

 like border of long, thin, rounded scales atUiched only by their inner margins, 

 about twelve to each interbrachial space. Only one arm-spine, which is 

 attached to lower edge of side arm-plate, and is a broad rounded scale like 

 those on the marginal border. No tentacle-scales. Color in alcohol, pale 

 brown. 



Station 171, 600 fathoms, 1 specimen (young). Station 174, 210 - 600 fathoms, 

 1 specimen. 



OPHIOBYRSA* gen. nov. 



Entire animal clothed in a thick skin, which hides the underlying plates, and 

 is beset on the disk with spines. Ann nearly cylindrical. Side arm-plates 

 projecting as short flap-like spine-ridges, which bear slightly rough spines on 

 their outer edge. Tentacles large and simple. Few or no mouth-papillx% but 

 at apex of mouth-angle the teeth and tooth-papilla) are represented by a clump 

 of little spines. Two large genital openings in each interbrachial space. 



Ophiobyrsa rudis sp. nov. 



Plate VIII. Figs. 198 - 200. 



Special Marks. — Disk closely covered with short spines. Arms very long, 

 tapering, and nearly cylindrical. Six short arm-spines. 



Description of an Individual (Station 161). — Diameter of disk 28 mm. 

 Length of arm 300 mm. Width of arm witliout spines 3.5 mm. One small 

 short, delicately pointed mouth-papilla on each side of the mouth-angle, and at 

 the apex a clump of short, sharp, spine-like papillae, which occupy the place of 

 teeth. Mouth-shields obscured by thick skin ; only their rounded outline may 

 be distinguished. Side mouth-shields and upper arm-plates entirely concealed 

 by thick skin. Side arm-plates project to form a thin, short, Hap-like spine- 

 ridge. On the upper surface of the arm there are two longitudinal rows of 

 very short, stout spines arranged in pairs, and usually standing on tubercles. 

 Disk five-sided and rather thin, covered by a thick skin, which is closelj' and 

 evenly beset above and below with short, stout, smooth, sharp spines or thorns ; 

 they are somewhat longer and more numerous near the margin of the inter- 

 brachial spaces, and are almost wanting just over the base of each arm. Six 

 equal, short, blunt, flat, somewhat rougli arm-spines, partly covered ])y skin, 

 not so long as an arm-joint, and placed on the edge of side arm-plates. Ten- 

 tacles large, simple, and round. No tentacle-scales. Color in alcohol, disk 

 yellowish broAvn ; arms the same, but much lighter. 



Station 161, 38 fathoms, 2 specimens. 



* 6<pts, snake ; pvp(xa, skin. 



