154 THE VOYAGE OF H.M.S. CHALLENGER. 



Side arm plates feeble, nearly or quite meeting above, but not below. Ujiper arm plates 

 nearly twice as wide as long, of a transverse oval shape, with inner curve deeper than 

 outer. Disk delicate 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. Radial 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. Colour in alcohol, pale grey. 

 Station 162. — April 2, 1874; oif East Moncceur Island, Bass Strait; 38 fathoms; 

 sand. Station 212.— January 30, 1875 ; lat. 6° 55' N., long. 122° 15' E. ; 10 to 20 

 fathoms ; sand. 



Ojihiocnida scahra, Lym. (PI. XIX. figs. 4-6). 



OpMocmida scabra, Lym., Bull. Mus. Comp. Zool., vol. vi., part 2, p. 33, pi. sii. fig?. 

 344-346, 1879. 



Disk much puffed. Radial shields long and narrow. Five or six short, stout arm 

 spines, the second longest. Two minute mouth papillte on either side, and a pair of 

 larger ones at apex of mouth angle. 



(Type specimen from 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 interbraehial 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 imiformly scaled, with about six 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 ai'm plate, 

 *5, 7, '4, "3, "3, '2 : '3. One round tentacle scale. Tentacles papillose, as in Ophiothrix. 

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



Station 128.— September 14, 1873 ; ofi" Bahia, Brazil ; lat. 13° 6' S., long. 38° 7' W.; 

 1275 fathoms; mud. 



This eccentric species might almost as well go with Ophiactis. 



