120 Mr. A. H. Clark on o@ 
rounded thorny summits, instead of being more or less 
conical, 
The arm-spines are six mm number, finely spinous, the 
uppermost the longest, the following regularly decreasing 
in length as in O. vestitus; the longest arm-spine (the 
uppermost on the second side arm-plate beyond the disk) is 
15 mm. long. 
The arms and the structures about the mouth do not 
seem to differ from the corresponding parts in O. vestitus. 
Type. Cat. no. 88585, U.S.N.M., from ‘ Albatross ’ 
Station 2818, among the Galipagos Islands, in 892 fathoms. 
Ophiophyllum marginatum, sp. un. 
The disk is approximately circular, 7°5 mm. in diameter, 
flat, and very thin, with the central portion covered with 
rather large, subequal, rounded, slightly imbricating scales, 
The arms are all broken, but were apparently short, 
tapering rapidly from the base, strongly flattened, and low 
triangular in section. The diameter of the arms at the base 
is 1:75 mm. 
In each interbrachial space there is a conspicuous fringe- 
like border consisting of from eight to ten (usually nine or 
ten) fish-scale-like plates, always with a central pair, which 
increase in size and length outward from the median line. 
The plates of the central pair are oblong, with the outer 
corners slightly rounded, slightly broader than high to one- 
third again as broad as high; the plates of the next pair 
are rhombic, slightly larger than those of the central pair, 
all of the sides the same length, the angles slightly rounded ; 
the plates of the following pair are more oblique than those 
of the second pair, and are markedly higher than broad ; 
the plates of the succeeding pair are larger, with a straight 
inner, but more or less curved outer, border, and a slightly 
curved free outer edge,in shape not unlike the primary 
(fore wing) of a butterfly ; the plates of the outermost pair 
are triangular, with the outer sides and the distal apex 
rounded, the latter reaching to the outer corner of the plate 
of the preceding pair. ‘The plates of each pair dorsally 
overlap the inner borders of the plates of the succeeding 
pairs. The distal borders of these marginal plates form a 
very slightly curved line between the arm-bases, in contrast 
to the much more strongly curved border of the disk. The 
outer sides of the plates of the outermost pair only slightly 
overlap the outer proximal corners of the first side arm- 
plates. 
