THE STARFISHES OF THE HAWAIIAN ISLANDS. 1063 
Abactinal plates flat, roundish, or not very regular polygonal in shape. A definite medio-radial 
row can be distinguished, the other plates being arranged in more or less parallel series, decreasing in 
size toward margin and tip of ray. Each plate is covered with large, close-set, flattish, very irregular 
valve-like granules, those about the border being smaller than the centrally situated ones. Scattered 
over disk and basal portion of rays are many large bivalved pedicellarise, which are oblong in shape 
when viewed from above. Conspicuous papulae emerge singly from sutures between the plates and 
are generally distributed except at end of ray. 
Marginal plates are conspicuous, numerous, devoid of either spines or pedicellarise, somewhat 
convex. They are covered with rather large, flat, round, hexagonal or irregular granules. 
Adambulacral plates massive, nearly quadrate, with a variable and irregular but not prominent 
armature. Armature as follows: (1) A furrow series of about 2 or 3 short, stubby, very robust 
spines, flattened in a horizontal plane, and with truncate or irregular tips. Middle spine is often 
shorter than the 2 laterals; or occasionally a very large bivalved pedicellaria stands at the margin in 
place of the spines. (2) On the actinal surface 8 to 12 large, irregular, depressed, spaced, quadrate 
and polygonal granules of different sizes, and arranged without constant order. When a suggestion 
of 2 irregular longitudinal series can be seen, the inner has much larger granules. Bivalved 
pedicellarise frequently replace some of the granules. No prominent spines on the actinal surface of 
any of the adambulacrals. 
Mouth plates narrow, and slightly convex actinally. Armature consists of about 5 robust furrow 
spines, the inner massive, blunt, and subprismatic, with flattened side to actinostome. The actinal 
surface is covered with granules similar to those of the adambulacrals. 
Actinal interradial areas well developed, paved with large actinal intermediate plates arranged in 
not very regular series parallel to furrow. These plates are very irregularly subquadrate to polygonal, 
and are covered with heavy, quadrate, oblong, or roundish granules, the exposed surfaces of which 
are flat. The plates adjacent to the adambulacral are larger than the others, and each bears a large 
bivalved pedicellaria surrounded by a single series of granules. Other smaller -pedicellariae are scat- 
tered over the rest of the interradial area. 
Madreporic body of medium size, subcircular, convex; situated one-third distance from center of 
disk to extreme margin. It has no striae, but is perforated with irregular pores of conspicuous size. 
Gilbertaster anacanthus, new species. 
PI. XXVII, figs. 2, 2a-2c. 
Rays 5. R=65 mm.; r=22 mm. R=3r. Breadth of ray at base (between second and third 
superomarginals) 16 mm. ; half w r ay between base and extremity, 10 mm-. 
Rays rather long and narrow', tapering abruptly at base, and then very slightly throughout rest 
of distance to the blunt extremity. Disk of fair size and rays inflated. Marginal plates well rounded. 
No spines of any description on general surface of body. Very large, low, sessile, bivalved pedicellariae, 
on actinal and abactinal surfaces but not on marginal plates. 
Abactinal area is paved with close-set, flat, roundish, or not very regular polygonal plates. A 
definite medio-radial series can be distinguished, the other plates being arranged in more or less regular 
rows parallel with it, decreasing in size toward the tip of ray and margin of body. Each plate is 
covered with close-set, superficially flat, large, very irregular granules. Those about the border of 
plate are smaller than the centrally situated ones, and form a very irregular peripheral series. The 
central granules, 2 to 6, are elongate, roundish, or rarely polygonal, while many have grotesque out- 
lines quite impossible to describe. On small plates in the interradial areas, there is usually only a 
single large central granule. The exposed surface of granules is usually very slightly rounded or convex. 
Scattered over the disk and basal portions of arms are many large bivalved sessile pedicellarise, which 
are oblong in shape when viewed from above. They average 1.5 mm. in length and are most 
numerous in interradial areas, extending thence as a single series along either side of the ray, just 
adjacent to superomarginals. They are absent from the median radial series of plates except rarely 
near center of disk. Each pedicellaria is so large that it extends quite across its plate, occupying the 
greater part. An interrupted series of granules surrounds it. The jaws are faintly toothed or serrated 
on opposing faces. Those pedicellarise half way between center of disk and margin are largest 
(attaining 2 mm. in length); the smallest are adjacent to superomarginals. Conspicuous papulae 
emerge singly from sutures between plates,, and are generally distributed except at the very tip of ray. 
