1042 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
taken also at the following stations: 3981, southeast of Kauai, 636-414 fathoms, globigerina ooze; 
3995, north of Kauai, 427-676 fathoms, fine gray sand and rocks; 3998 southwest of Kanai, 235-228 
fathoms, coarse brown coral sand, shells, rocks (very young, probably this species) ; 4007, vicinity of 
Kauai, 508-557 fathoms, gray sand, foraminifera (very young). All, but types are immature 
specimens. 
Cheiraster horridus, new species. 
PI. x, fig. 5, 5a; pi. xvn, fig. 3; pi. xvm, fig. 2. 
Rays 5. R=35 mm.; r=7 mm. R=5r. Breadth of ray at base (between first and second supero- 
marginals) 7 mm. 
Rays rather short for genus, tapering very gradually from a narrow base to pointed extremity, 
which is reflexed. The ray tapers more perceptibly in outer than inner half, giving a stout appear- 
ance. Disk small. Interbrachial arcs regular but well rounded. Lateral walls vertical. Marginal 
plates form a broad, but not raised, border to abactinal area. Abactinal surface of disk and rays 
subplane; actinal areas subplane; margins of rays well rounded. No pedicellarise whatsoever. 
Abactinal paxillse are fairly large and distinctly spaced, the plates varying in size and having no 
definite order. They are irregularly hexagonal, or polygonal, and the convex, spine-bearing surface 
is only slightly raised above level of sutures. Larger paxillse of disk bear 15 to 20 small cylindrical 
spinelets, surrounding in 1 or 2 irregular series a long, slender cylindrical spine (3 to 4 mm.) which 
stands erect. These spines are numerous on disk, and about 10 scattered, very large paxillse bear 
from 2 to 4 accessory spinules about half as long as the spine. On a few of the paxillse a rosette of 
enlarged spinelets surrounds base of spine. On rays the spines are numerous, but reduced to one- 
third or one-fourth the size of those on disk; deciduous and usually not more than 1 to a paxilla. 
Scattered among the larger paxillse of disk are numerous small ones, consisting of a central spinelet 
and 4 to 9 in a rosette surrounding it. Very small paxillse bear a group of 3 or 4 spinelets. Papulse 
are few, very inconspicuous, and are confined to the basal portion of each ray. No specialized 
papularium is evident. 
Marginal plates form a conspicuous border to disk and rays. Plates of the two series are not 
exactly opposite (except the first pair), but alternate, so that the sutural line between the 2 series is 
regularly zigzag. Superomarginal plates, about 20 in number from median interradial line to 
extremity of ray, are about as wide as high, except in interbrachial arc, where height is greatest. 
They form a conspicuous margin to paxillar area, which on arms is equal to twice the width of 1 series 
of plates. First plate much smaller than succeeding. Each superomarginal on outer or marginal 
angle bears a conspicuous slender, tapering, sharp spine, 2 to 3 mm. in length, which stands out at 
right angles to side of ray. They decrease in size toward tip of ray, and are surrounded each by 2 to 
6 smaller spinules of different lengths, the longest being about one-half length of spine. Rest of 
plate is covered with tiny, spaced spinelets. There are prominent but shallow furrows between 
the plates. 
Inferomarginals are distinctly tumid, and form a rounded and elevated border to the actinal 
surface. Each plate bears from 5 to 8 slender, tapering, bristling spines and spinules, either disposed 
in an oblique transverse group, or (on outer half of ray) forming a more compact group on lateral 
surface of plate. The spines are of different lengths, the longest being equal to superomarginal spine. 
There are usually 3 nearly as long, while the remainder vary from one-third to one-half the length of 
longest. Scarcely 2 plates have the armature arranged exactly alike. General surface of plates is 
covered with small, slender, sharp spinelets, rather widely spaced. A number in the vicinity of 
spines are enlarged. 
Adambulacral plates have a prominent angular projection toward furrow, the furrow margin being 
rounded or semicircular in outline. Armature as follows: (1) A palmate furrow series of 5 or 6 slender, 
untapered (or but very slightly tapering), flattened, round-tipped spinelets, the median longest and 
all slightly radiating. Along adoral margin of plate there are 2 to 4 tiny, slender spinelets, simulating 
a continuation of the furrow series. (2) On actinal surface of plate are 2 robust, tapering, acute 
spinules forming an oblique series, the axis of which would extend diagonally across the plate from 
outer adoral to inner aboral corner. The outer spine is longest (2 mm. on inner half of ray), the 
inner about equaling longest of furrow spinelets. One or 2 of the delicate adoral thornlets are some- 
times found in close proximity to the larger spine. 
