260 BULLETIN OF THE 



Description of an Individual. — Diameter of disk 12 mm. Width of arm 

 3 mm. Six spaced and rather long mouth-papillae to each angle. Five thick 

 teeth, of a short oval shape. Mouth-shields very short and wide, rudely 

 transverse oval in form ; length to breadth, 1 : 2.5. Side mouth-shiekls much 

 longer than wide, of nearly equal width except at their outer ends where they 

 taper ; they fully meet within. First under arm-plate of a transverse diamond- 

 shape with rounded angles ; the next two are squarLsh, with a curved outer 

 side ; those beyond are nearly semicircular, with a slight peak within ; all 

 are narrow, occupying not more than one third the width of the arm. Side 

 arm-plates stout and forming a well-marked spine-ridge ; they meet below and 

 sejDarate all except the first two upper arm-plates ; they, however, do not meet, 

 and there is a pit between their upper ends ; also they are so short as to leave 

 a band on sides of arm quite uncovered. Upper arm-plates transverse oval 

 with somewhat pointed corners ; they are nearly twice as broad as long and 

 cover only about half the width of the arm. Disk-scales very indistinct, ex- 

 cept near radial shields, which are separated, small, short and rounded ; length 

 to breadth, 1.3 : 2. Upper surface of disk sparsely set with sniootli grains. 

 Lower interbrachial space smooth and apparently with few or no scales. Gen- 

 ital openings large and extending from the mouth-.«liield to margin of disk. 

 Seven arm-spines, of which the three lowest are very small, microscopically 

 rough, and not hmger than half a joint ; whUe the three uppermost are often 

 as long as one and a half or two joints, stout, nearly cylindrical, and tapering 

 to :. blunt point. On some of the basal pores there is a minute tentacle-scale 

 attached at the juncture of under and side arm-plates. Color in alcohol, pale 

 brown. 



" Challenger " Expedition, Station 235, 34° 7' N., 138^ E., 565 fathoms. 

 Water 3°. 3 Cent. Mud, One specimen. 



The species is nearest 0. tuberculosa; but has seven instead of three arm- 

 spines. 



Ophiacantha anomala ? G. 0. Sars. 

 Station 306, 41° 32' 50" N., 05° 55' W., 524 fathoms. 



Ophiacantha bidentata Ljn. 



Station 307, 41° 29' 45" N., 65° 47' 10" W., 980 fathoms. Station 308, 

 41° 24' 45" N., 65° 35' 30" W., 1242 fathoms. Station 324, 33° 27' 20" N., 

 75° 53' 30" W., 1386 fathoms. Station 338, 38° 18' 40" N., 73° 18' 10" W., 

 922 fathoms. Station 339, 38° 16' 45" N., 73° 10' 30" W., 1186 fathoms. 

 Station 340, 39° 25' 30" N., 70° 58' 40" W., 1394 fathoms. Station 341, 

 39° 38' 20" N., 70° 56' W., 1241 fathoms. Station 342, 39° 43' N., 70° 55' 25" 

 W., 1002 fathoms. 



Ophiacantha abyssicola G. 0. Sars. 

 Station 309, 40° 11' 40" N., 68° 22' W., 304 fathoms. 



