MUSEUM OF COMPARATIVE ZOOLOGY. 101 
on each side. Three long, slender, cylindrical, sharp, tapering arm-spines, 
situated close together low on the outer edge-of the side arm-plates ; lengths to 
that of an arm-joint 1.2, .8, .6: .6. Color iu alcohol, white. 
A young, with a disk of 3 mm., differed in having the upper disk covered 
almost entirely by the primary and the other large plates ; the intermediate 
disk-scales were just beginning to form. The radial shields were shorter, and 
the papille above the arm fewer. 
Kerguelen Islands, 120 fathoms, 12 -+ specimens. Prince Edward’s Island, 
85-150 fathoms, 7 specimens (same species?) Station 152, 1260 fathoms, 
4 specimens. 
Ophiocten umbratieum sp. nov. 
Plate V. Figs. 131, 132. 
Special Marks. — Primary and marginal disk-plates small, and the former 
widely separated. Arm-comb feeble. Tentacle-scales single and minute, or 
quite wanting. 
Description of an Individual (Station 325). — Diameter of disk 9.5 mm. 
Width of arm close to disk, without spines, 1.3 mm. Four rather wide, closely 
joined mouth-papille, with one larger, diamond-shaped, at apex of the jaw. 
Mouth-shield very thin, triangular, broader than long, with blunt angle inward 
and corners rounded ; length to breadth 1 : 1.5. Side mouth-shields long and 
narrow, tapering inward, where they nearly or quite meet. First under arm- 
plate large, four-sided, the inner side being very short like a truncated angle, 
with corners rounded ; the rest of the under arm-plates are very small, nearly 
or quite semicircular, with a little peak inward, Side arm-plates slightly flar- 
ing outward, meeting broadly below, where they form most of the under surface 
of the arm ; separated above by upper arm-plates, which are four-sided, with 
outer edge wider than inner, and curved ; lateral sides slightly re-énteringly 
curved. Disk flat and thin, covered with small, transparent, delicate scales ; 
six small, rounded, widely separated primaries, one in the centre and one to each 
brachial space ; outside these there are two similar plates in each interbrachial 
space, one towards the centre and one near the margin ; along the margin there 
are two irregular rows of small plates, somewhat broader than long. Radial 
shields triangular, with a rounded angle inward, widely separated by the disk 
scaling ; length to breadth 1.5: .8. Lower interbrachial space covered by deli- 
cate, nearly transparent scaling, which also hides the genital scales, except their 
outer tips, just outside the radial shields, which bear an arm-comb of three or 
four minute papille. Genital opening quite long, extending from the outer 
end of side mouth-shields to edge of disk. There are large tentacle-pores, but 
no scales on any of the pores. Near base of arm there are three small, delicately 
tapering arm-spines, situated on the outer edge of the side arm-plate ; the 
upper is about two thirds the length of an arm-joint and the lowest about half 
as long ; farther out there are but two spines, Color in aleohol, white. 
On the above specimen no tentacle-scales could be seen, but on others some 
pores, at any rate, are furnished with a single minute one. 
Station 325, 2650 fathoms, 7 specimens. 
