MUSEUM OF COMPAKATIVE ZOOLOGY. 33 



Description of an Individual (Station 162). — Diameter of disk 5.2 mm. Arm 

 broken, but aj^parently eight or ten times the diameter of disk. Width of arm 

 near disk 1.2 mm. The short narrow mouth-angle has at its base on either side 

 a spiniform pa^^illa, and at its apex a pair, stouter and more angular. Mouth- 

 shields longer than broad, nearly oval. Side mouth-shields triangular, some- 

 what curved round the mouth-shield, not meeting within. Under arm-plates 

 narrow, longer than broad, with eight sides, but having the angles rounded and 

 nearly obliterated ; lateral sides re-enteringly curved. Side arm-plates feeble, 

 nearly or quite meeting above, but not below. Upper arm-plates nearly twice 

 as wide as long, of a transverse oval shape, with inner curve deeper than outer. 

 Disk delicfite but rather thick, sparsely set above and below with small spines ; 

 in the centre may be seen some round, very thin, primary plates ; the rest seems 

 naked, but on drying a very fine, delicate scaling appears. Eadial shields much 

 longer than broad, slightly curved, meeting without, widely separated within ; 

 length to breadth 1 : .5. Five cylindrical, tapering, blunt arm-spines, the 

 lowest somewhat the longest ; lengths to that of an under arm-plate, .5, .5, .5, .5, 

 .7 : .5. No tentacle-scales. Color in alcohol, pale gray. 



Station 162, 38 fathoms, 2 specimens. Station 212, 10-20 fathoms, 1 speci- 

 men. 



Ophiocnida seabra sp. nov. 



Plate XII. Figs. 344-346. 



Special Marks. — Disk much puffed. Radial shields long and narrow. Five 

 or six short stout arm-spines, the second longest. Two minute mouth-papillae 

 on either side, and a pair of larger ones at apex of mouth-angle. 



Description of an Individual (Station 128). — Diameter of disk 6 mm. Length 

 of arm about 40 mm. Width of arm near disk 1.3 mm. Two minute, bead- 

 like papillae on each side of base of small mouth-angle, and a pair, much larger, 

 at its apex. Mouth-shields small, rounded, about as broad as long. Side 

 mouth-shields small, bent, wider 'without than within, where they do not meet. 

 Under arm-plates as broad as long, bounded by a curve without, and within by 

 three sides of an octahedron. Side arm-plates narrow, widely separated above 

 and below, and having a feeble spine-ridge. Upper arm-plates two and a half 

 times as broad as long, of a clean, transverse oval shape. Disk extremely puffed 

 in the interbrachial spaces by the swollen ovaries. This swollen portion, both 

 above and below, is naked, and sparsely set with minute, peg-like spines ; but 

 above the surface is finely and pretty uniformly scaled, with about 6 scales 

 in the length of 1 mm. Radial shields long and very narrow, slightly bent 

 towards each other, nearly or quite separated their whole length by a narrow 

 strip of two scales ; length' to breadth 1.5 : .3. Six short, thick, microscopically 

 thorny arm-spines, whereof the two uppermost are longest, somewhat flattened, 

 pointed, and have a minute beak ; those below diminish constantly in length, 

 and are almost club-shaped ; lengths to that of a lower arm-plate, .5, .7, .4, .3, 

 .3, .2 : .3. One round tentacle-scale. Tentacles papillose, as in Ophiothrix. 

 Color in alcohol, pale yellowish-brown, mottled and speckled with darker. 



VOL. VI. — NO. 2 8 



