MUSEUM OF COMPAEATIVE ZOOLOGY. 139 



Ophiacantha rosea sp. nov. 



Plate X. Figs. 267, 268. 



Special Marks. — Disk-scales and radial shields hidden by a thick skin, 

 which is closely beset with very short, stout spines, which sometimes are no 

 higher than grains. Eleven arm-spines, slightly rough under microscope. 



Description of an Individual (Station 308). — Diameter of disk 17 mm. Length 

 of arm, 68 mm. Width of arms without spines 4.5 mm. Mouth-papillae 

 irregular ; there are usually five on the inner part of the angle, flattened and 

 blunt ; and outside these, near end of mouth-slit, a group of from three to six 

 irregular papillae, short and flattened. Eight or nine teeth, shaped like blunt 

 spear-heads. Mouth-shields and side mouth-shields closely joined and covered 

 with thick skin, so that their outlines are not clear. Under arm-plates shield- 

 shaped, with an angle within, a curve without, and re-entering curves on the 

 lateral sides opposite the large tentacle-scales. Upper arm-plates with distinct 

 outlines, broad fan-shaped, Avith a rounded or very obtuse angle inward. Side 

 arm-plates, near base of arm, barely meeting above and below, and having a 

 narrow projecting spine-ridge. Disk puffed, densely and evenly beset, with 

 very short, stout, conical spines, which to the naked eye seem nearly like 

 large grains ; scales and radial shields entirely covered. Eleven stout, blunt, 

 regular, cylmdrical arm-spines, which, under the microscope, are slightly rough. 

 Lengths to that 'of an arm-joint 3.5, 4.7, 4, 3.8, 3.8, 2.8, 2.5, 2.5, 2.5, 1.2. .8 : 

 1.3. One very large, thick, pointed tentacle-scale, over 1 mm. long. Color 

 in alcohol, pale rose-pink above ; below yellowish. 



Specimen from the distant station 145 differed only in having larger spines 

 on the disk. A young one, with a disk of 7 mm. had only seven mouth- 

 papillae to each angle ; the additional papillae at the outer end of mouth-slit had 

 not yet appeared ; the disk-spines were forked and thorny, and the eight arm- 

 spines were rough and almost thorny. 



Station 145, 310 fathoms, 8 specimens. Station 308, 175 fathoms, 12 + 

 specimens. Station 236, 420 - 775 fathoms, 1 specimen. 



Ophiacantha imago sp. nov. 



Plate X. Figs. 375, 276. 



Special Marks. — Disk regularly set with small, short, thick stumps, each 

 bearing a crown of blunt thorns ; tentacle-scales small and pointed ; six short, 

 opaque, cylindrical, scarcely thorny arm-spines. 



Description of an Individual (Kerguelen Islands). — Diameter of disk 8 mm. 

 Length of arm 37 mm. Width of arm without spines 1.6 mm. Seven short, 

 stout, blunt, close-set mouth-papillae ; the innermost are a little the largest. 

 Four flat, rather thick teeth, all squarish, except uppermost one, which is 

 pointed. Mouth-shiulJs small, of a rounded diamond-shape. Side moutli- 

 shields short, wide, slightly curved, not meeting within. They and the mouth- 



