THE STARFISHES OF THE HAWAIIAN ISLANDS. 
1059 
Adambul acral plates have a straight margin to furrow. The width of each plate is about two- 
_ thirds the length. The armed portion of actinal surface has the appearance of being more or less 
elevated above the level of the furrow margin. Armature as follows: (1) A furrow comb of 12 to 15 
straight, untapered, slightly flattened, roundly tipped spinules, standing parallel. The proximal 
plates bear usually 12 spinules; those more distantly situated 14 or 15, while the plates at the tip of 
the ray only about 9. The lateralmost spinelets are shortest. A very characteristic feature of these 
spinules is that their tips do not conform to a straight or a regularly curved line, but rather to a 
compound curve. That is, the adoral half of the series is longer than the aboral, the exact relations 
showing better by figure than description. . (2) The actinal surface of proximal plates bears about 6 
erect, stout, tapering, sharp, movable spines disposed in 2 regular, or irregular, longitudinal series, or 
else without very definite arrangement. They average from 5 to 7 mm. in length. One of them is 
usually longer than all the rest, while frequently 1 or 2 others are not more than half as long as the 
longest. These actinal spines are reduced to 3 or 4 at about the middle of the radius, and to 2 on the 
outer attenuate portion of the ray. They are then arranged in an oblique transverse series, on the 
aboral half of the plate, the axis of the series running from the inner aboral corner to the middle of 
the outer edge. Proximal adambulacrals bear fewer actinal spines in medium sized and small 
individuals. Numerous large, irregularly subprismatic or squamiform granules are grouped about the 
border of each plate, except, of course, on the furrow margin. 
Actinal interradial areas are very large, the intermediate plates extending along ray to nineteenth 
inferomarginal (from median interradial line) or to within 2 plates of the point where superomarginals 
of adjacent sides join medially. The plates are large, distinct, flat or slightly convex, irregularly 4 or 
5 sided (occasionally hexagonal), those adjacent to the adambulacrals largest and most regular. All 
plates decrease in size as they approach the margin. They are covered with coarse, roundish, or sub- 
squamiform granules, a peripheral series of smaller, closer ones being usually distinguishable. Each 
plate bears a central, sharp tapering prominent spine about 5 mm. in length. The plates adjacent to 
adambulacrals usually bear 2 or 3 in a transverse series, these being longer than the spines over 
remainder of interradial area. Likewise the proximal plates of the next 2 longitudinal series bear 
each 2 spines. 
Mouth plates are small and narrow, the width of the united pair being equal to one-half the inter- 
radial dimension. Companion plates together form a sharp mouth angle with a long free margin. 
Marginal spinules 14, like those of adambulacrals, the innermost being somewhat enlarged and sub- 
prismatic. Actinal surface of each plate bears 8 robust, erect, sharp spines (like those of the adam- 
bulacral plates) in an irregular interradial row, with 1 or 2 odd spines in the corner adjacent to first 
adambulacral. There is great variation in the arrangement of these opines. Often there is a series 
of 4 parallel with the furrow margin, and a row of 3 to 5 extending thence o outer end of plate, decreas- 
ing in size outward. Margin of plate (excepting toward furrow) is lined with an irregular series of 
large, robust, subprismatic, or often subspinose granules. The odd actinal interradial plate adjacent 
to the outer end of the combined mouth plates bears 6 to 9 spines. 
Madreporic body is circular, convex, with irregular striations. It is situated near the center of 
disk, about 12 mm. from anal opening (one-seventh distance from center to edge of disk). 
In a medium-sized specimen examined the abactinal plates of the radial and either adradial series 
are distinctly 6-lobed. The other plates of the papular area, on either side of these, rapidly lose the 
lobed character. Near the primary radial plates the lobes become detached and form internal short 
radiating ossicles (4 to a plate) joining neighboring plates. The lobed plates touch each : other by the 
lobes, usually only 4 lobes (2 on either side of plate) being sufficiently enlarged to impinge regularly 
on those of laterally situated plates. Each radial plate is thus joined to 2 adradials on each side. 
There are 5 large polian vesicles, and 5 conspicuous, distally bifid intestinal coeca. Interradial septa 
single, uncalcified. 
Color in life: Abactinal surface bright cadmium yellow except the radial papular areas, and a 
circular area about the anus (bounded externally by the madreporic body), which are bright madder 
pink. The erect spines are whitish. Dorsal surface of superomarginal plates, except on outer third 
of rav, madder pink. The abactinal area of pink is lanceolate in shape, and about the border grades 
into the yellow area. The enlarged granules here are pink, while the rest of the plate is yellow. 
Many of the granules are deeper colored than the general tint. Actinal surface whitish. 
Variation and young: This species is subject to a certain amount of variation which appears to be 
mainly due to age. There is represented in the collection every gradation in size from the smallest, 
