THE STARFISHES OF THE HAWAIIAN ISLANDS. 
1007 
Rays are fairly broad at base, tapering continuously to extremity, which is sharp. Interbrachial 
arcs subacute, very slightly rounded. Abactinal paxillar area plane; no epiproctal protuberance. 
Paxillse of abactinal surface are large and uniform on arms, but of various sizes on disk, where the 
largest paxillse occur. Each consists of a very short rounded basal portion, surmounted by a group of 
6-16 relatively long, slender spinelets, which radiate from the pedicel top. Of these 1 to 3 or 4 are 
usually central, the remainder forming an irregular series about them. Usually the spinelets form a 
widely radiating group, the central ones being stouter than those about the periphery. Very small 
paxillse with only 1 to 4 or 5 spinelets are scattered over disk; and at end of the ray these predominate. 
Papulse large, confined to border of paxillar area, there being none on median radial areas of ray, or 
on central portion of disk. 
Superomarginal plates, which are 14 in number from median interradial line to extremity of ray, 
are about as high as broad in the middle of the ray, higher than broad at the base, and broader than 
high at the extremity. The plates are set very slightly oblique in relation to the long axis of ray, 
and each when viewed from above is about as long as broad, except in interbrachial arc, where the 
plates are narrower. They form a nearly right-angled margin to ray. Each bears on the edge formed 
by the lateral and dorsal superficies a small cylindrical spinule, placed nearer aboral margin than 
center. Those on first 2 superomarginals are not larger than others. The plates are beset with rather 
widely spaced, slender, papilliform spinelets. 
Inferomarginal plates are broader than high, and do not extend laterally beyond the superior 
series. Each plate bears an oblique comb of 3 or 4 lateral, delicate, cylindrical, tapering spines, the 
line of the base forming an angle of about 45° with the transverse axis of the plate and tending from 
the upper adoral corner downward and aborally. The adoral is the smallest, and most laterally 
situated. The third from this is the longest; the second is intermediate in size, and the fourth is 
usually slightly longer than second and nearly as long as third, but on outer half of ray may be much 
shorter than either second or third. Basalmost inferomarginal bears but 2 or 3 spines. A small 
spinule is sometimes present on the aboral side of the plate a little distance from the comb. Surface 
of inferomarginal plates is covered with delicate, slender, papilliform, subcapillary spinelets, which 
show no tendency to become squamiform. 
Armature of adambulacral plates consists of (1) a furrow series of 3 spinelets and (2) a group of 8 
or 10 actinal spinelets arranged in either 2 or 3 irregular longitudinal series. Furrow spinelets long 
and slender, bluntly pointed, the' median spinelet longest, and at the base somewhat flattened (in axis 
crosswise to furrow). They usually stand perpendicularly to plate. On outer half of ray the first 
series of the actinal group consists of 4 long, very slender cylindrical spinelets, standing upright. The 
one at the aboral end of series stands on the furrow margin, aborad to lateral spinelet of furrow series, 
so that the latter appears often to consist of 4 spinelets. On these plates the second actinal series also 
consists of 4 spinelets, shorter and slenderer, which, by reason of the obliquity of the plate, extend 
further aborally than the furrow series. Toward base of ray there are usually 3 series of actinal 
spinelets, very irregular in arrangement, with 3 spinelets to each series, and an odd spinelet between 
the furrow and first actinal series. The aboral spinelet of the latter is always situated in line with 
furrow series. One or 2 small spinelets may be added at outer end of plate. 
Actinal intermediate plates, 18 in number to each interradial area, show a tendency to encroach 
upon base of ray. Actinal interradial areas rather pronounced for an Astropecten. Each plate is cov- 
ered with 5 or 6 very delicate subcapillary spinelets, similar to but smaller than those of actinal 
surface of adambulacrals. 
Mouth plates of moderate size. Their whole surface is covered with small slender cylindrical 
spinelets disposed in three series — a marginal, a superficial, and an intermediate (pi. ii, fig. 3d). 
The innermost spine of the marginal series is much enlarged, forming with its companion 2 stout, 
blunt, cylindrical teeth at each mouth angle. 
Madreporic body small, with very coarse ridges; situated close to margin. 
Color in alcohol, ashy white. 
Locality: Station 3937, vicinity of Laysan Island, 130-148 fathoms, white sand and small shells; 
bottom temp. 63°; 1 specimen, type no. 21143, U. S. National Museum. 
This species differs from its nearest relative, A. pectinatus, in the following respects: Character of 
abactinal paxillse, those of pectinatus having more numerous, shorter spinelets; disposition of papulae; 
character of spines on inferomarginals; character of adambulacral armature, that of pectinatus being 
