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



meeting below, but well separated above by the thick, broad, somewhat arched upper arm 

 plates, which are wide fan-shaped, with a blunt angle inward. Under the microscope 

 they appear minutely tuberculous, while the lower plates are ornamented with wavy 

 lines. Disk thick and nearly round, completely covered with coarse, rounded granules, 

 five or six in the length of 1 mm. on the upper surface, and more scattered below. The 

 underlying scales are extremely thin and smooth. Genital openings long, extending 

 from outer corners of mouth shield nearly or quite to the margin of disk. Seven 

 long, smooth, cylindrical, tapering arm sjDines, the two upper ones as long as three 

 or four arm joints ; the others somewhat shorter. One long, wide tentacle scale, 

 with a rounded point occupying the lateral side of the under arm plate. Colour in 

 alcohol, nearly white. 



Station 150.— February 2, 1874; lat. 52° 4' S., long. 71° 22' E. ; 150 fathoms; 

 rock. Off Prince Edward Island ; 85 to 150 fathoms. Off Marion Island; 50 to 75 

 fathoms. 



Ophioconis pulverulenta, Lym. (PL XXIII. figs. 4-6). 



Oplrioconis pulverulenta, Lym., Bull. Mus. Comp. Zool., vol. vi., part 2, p. 45, 1879, pi. xiv. 

 figs. 377-379. 



Disk finely, closely, and evenly granulated, with about 14 grains in the length of 

 1 mm. Eight or nine long, delicate, somewhat flattened arm spines, the three uppermost 

 longest, and nearly equal. Two tentacle scales. 



(Type specimen from Station 172.) Diameter of disk 12 mm. Length of arm about 

 55 mm. Width of arm close to disk, without spines, 3*2 mm. Ten small, short, close- 

 set, pointed mouth papillae on each side of the mouth angle, and one somewhat stouter at 

 the apex ; the two outermost are broadest and most rounded. Mouth shields large, as 

 broad as long, of a rounded heart-shape. Side mouth shields stout and wide, broader with- 

 out than within, where they do not meet. Both they and the mouth shields are more or 

 less covered by a granulation, which, as well as that of the disk, is liable to be rubbed off. 

 Under arm plates axe-shaped, much broader without, where the edge is curved, and with 

 deep re-entering curves on the lateral sides. Side arm plates thin and microscopically 

 corrugated. Upper arm plates thin, with a central ridge, about twice as broad as long, 

 much wider without than within, with sharp outer lateral corners and straight sides. 

 Disk round and quite thick closely and evenly covered with minute granules, twelve 

 or fourteen in the length of 1 mm. Underneath these granules there are fine uniform, 

 overlapping scales, about five in the length of 1 mm., among which the radial 

 shields cannot be distinguished. Eight or nine long, slender, tapering, flattened arm 

 spines, whereof the three uppermost are about 2*3 mm. long and nearly equal, and 

 the other five or six from 2 mm. to 17 mm. long. Two long, thin, nearly oval 



