MUSEUM OF COMPARATIVE ZOOLOGY. X90 
Ophiacantha tuberculosa sp. nov. 
Plate VIII. Figs. 204, 205. 
Special Marks. — Disk wrinkled and beset with coarse grains ; four smooth 
stout arm-spines. 
Description of an Individual (Station 210). — Diameter of disk 6.5 mm. 
Length of arm 32 mm. Width of arm without spines 2 mm. Seven stout 
blunt mouth-papillo, whereof the innermost is spearhead-shaped and stands 
under the teeth, which are four in number, flat and square, with rounded cor- 
ners. Mouth-shields small, much wider than long, with an obtuse angle within 
and a little peak without; length to breadth .8: 1. Side mouth-shields short, 
nearly crescent-shape, with the curve outward ; scarcely meeting within. Un- 
der arm-plates thick and distinct, four-sided, somewhat broader than long, 
with outer side curved and the others nearly straight, except second plate, 
which is nearly pentagonal, with a very obtuse angle within. Side arm-plates 
slightly projecting, meeting narrowly below and not at all above. Upper 
arm-plates thick and well marked, four-sided, with outer corners rounded, 
much wider without than within, Disk contracted in interbrachial spaces, 
with deep radiating furrows between the narrow radial shields, which are com- 
pletely hidden, as well as the disk-scales, by the skin and by numerous small 
conical tubercles, which are larger and closer set on the radial shields. Four 
stout, blunt, cylindrical, smooth arm-spines ; upper one much largest ; lengths 
to that of an arm-joint 2, 1.4, 1, 1: 1. One rather small tentacle-scale, longer 
than wide, pointed, and not encroaching (as is usual in the genus) on the un- 
der arm-plate. Color in alcohol, very pale brown. 
This species is one of the most aberrant in the genus; the arm-spines, 
smooth and only four in number, and the minute disk-tubercles, instead of 
thorny grains, remind one rather of Ophiocoma. Indeed, Ophiacantha bidentata 
and O. vivipara, which somewhat resemble this species, have been described 
under Ophiocoma ; but the general structure is that of a tr ıe Ophiacantha. 
Station 210, 375 fathoms, 1 specimen. 
Ophiacantha vepratica sp. nov. 
Plate X. Figs. 245-247. 
Special Marks, — Disk closely beset with grains, among which are a few short 
spines. Seven not thorny, translucent, slender arm-spines. 
Description of an Individual (Station 171). — Diaméter of disk 6.5 mm. 
Length of arm about 30 mm. Width of arm without spines 1.8mm. Mouth- 
papille stout, conical, blunt, three on each side of an angle, and a larger odd 
one at the apex within, which is similar to the five teeth standing immediately 
above it. Mouth-shields small, about as long as broad, bounded within by an 
obtuse angle, and without by a deep curve or truncated angle; length to 
