THE STARFISHES OF THE HAWAIIAN ISLANDS. 
1013 
These spines are usually subequal, or the median slightly the longest, but occasionally near base of 
ray the uppermost spine is hardly half as long as the second. There are often 4, and rarely 5, spines 
on the first few plates, and the innermost spine is near the inner end of the plate, the others being 
subequally spaced. On outer portion of ray there is considerable irregularity in the spines, the 2 
upper often being placed in a longitudinal or oblique series near together, separated from the inner or 
third spine. Inferomarginal plates are further covered with small, papilliform spinelets, those on the 
upper end of the plate similar to granules of adjacent portion of superomarginal. They increase in 
length toward' the inner end of the plate, where they are much larger. 
Adambulacral plates with convex margin to furrow. The armature consists of 5 long, flattened, 
slender, round-tipped spines disposed in a fan-shaped series. The median spine is longest, somewhat 
saber-shaped, but round-pointed, and the lateral spines, which form a graduated series at either side, 
present their flat sides to furrow. The lateralmost furrow spines are really the lateral members of 
the first actinal series of 3, the central spine of which resembles the laterals. On the outer end of 
plate is a longitudinal series of 3 or 4 usually considerably shorter spines. When there are but 3 the 
spines average slightly larger. The armature as a whole has an expanded character resembling 
Astropecten in general. 
Mouth plates are small but prominent actinally, with a numerous armature regularly arranged. 
Marginal series consist of 6 flattened spinelets, of which 2 are placed at the inner angle as teeth, and 
4 form a graduated series along the edge of the plate toward furrow. Marginal series is continued 
along the edge of plate adjacent to first adambulacral as a row of numerous, shorter, and much slen- 
derer spinelets. The actinal surface bears a superficial series of about 15 slender, tapering spinelets 
placed along suture margin and increasing in size toward the teeth. A parallel series of 8 or 9 similar 
spinelets extends along surface of plate between marginal and superficial series, but this is lacking on 
the inner third of plate. i 
Actinal interradial areas are rather small; paved with fairly large, irregular, overlapping plates 
arranged in more or less regular series extending from inferomarginals to adambulacrals. These 
intermediate plates extend in a single (longitudinal) series nearly half the length of ray or to fifteenth 
inferomarginal, but the outer plates are very rudimentary. In the interradial areas the plates may be 
described as rudely shield-shaped, or oval, with a notched border. There is a prominent keel on the 
actinal surface of each, extending lengthwise of plate (interradially), and this keel forms a beak at 
the inner end of each plate, overlapping the outer edge of the adjacent plate. The plates consequently 
imbricate, and this is more pronounced in the large than in the small specimens. Armature consists 
of a series of radiating, slender spinelets of different lengths, placed in a peripheral irregular series 
about the keel. These spinelets are about the size of those covering the inner portion of inferomar- 
ginals. There is also a central enlarged, tapering spinule or group of 3 to 6 spinules, all forming a 
very ornamental paxilla crown on the keel. Those plates adjacent to the adambulacrals have rather 
larger spinelets than the others, and on ray their armature is arranged in a radiating coordinate group. 
"Usually the marginal spinelets on the outer side of the keel of all the plates are conspicuously the 
longest. These peripheral spinelets project over rather wide fasciolar furrows, between the carinations 
of the plates. 
Superambulacral plates are present, well developed on basal half of series but rudimentary beyond 
the middle of ray. Tube feet are conical, without sucking disks. Anal pore present, minute. 
Color in life nearly white, except the tips of the rays and a small area in the interbrachial arc 
on abactinal surface, which are carmine to bright vermilion or orange vermilion. The interbrachial 
area is triangular or crescent-shaped and the central portions of the paxil he are uncolored. In alcohol 
all the red disappears. 
Variations: The variations are all of a minor character and are mostly due to age. Aside from 
this, however, some difference is apparent among the specimens in the relative width of the inter- 
brachial arc and consequent tenuity of . arms, but this seems due to the degree of inflation of the 
paxillar area. There is one specimen with 6 rays. 
Young: The smallest specimen (R = 5 mm., r = 3 mm.), from the stomach of an adult, is quite 
different in general shape, the disk being large and the rays short and broad. Actinal intermediate 
areas are already prominent and the spinelets of actinal and granules of abactinal paxillae fewer in 
number. Mouth plates have but 2 series of spinelets, marginal and superficial; no inferomarginal 
spines. Adambulacral armature much as in adult. Most of the stages intermediate between this and 
the adult are represented. 
