MUSEUM OF COMPARATIVE ZOOLOGY, 131 
space are two regular transverse rows of long and narrow plates, Genital 
scales small, much 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 attached 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, Arm 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-papille, 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 without 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 papilla, 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, flap-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 closely 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 rough arm-spines, partly covered by 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 brown ; arms the same, but much lighter. 
Station 161, 38 fathoms, 2 specimens, 
* dois, snake ; Búpoa, skin, 
7 , t 3 
