THE STARFISHES OF THE HAWAIIAN ISLANDS. 
1053 
of the height of each plate exceeds the length. Two distal superomarginals are in contact medially at 
each disk angle. The general surface is smooth, though microscopically roughened with regular pits 
and bosses, but on it are about 30 scattered, low, round granules set in shallow depressions. These 
are usually absent from a narrow zone around the margin. A regular series of flat, roundish, bead-like 
granules surrounds each plate, and on the dorsal surface there are 1 or 2 small, 2-valved spatulate 
pedicellarise on a few of the plates nearest interradial line. Terminal plate is small, armed with a 
short, blunt spinelet. 
Inferomarginal plates encroach upon actinal area more than superomarginals upon abactinal; 
slightly tumid; twice as broad as high, forming a slightly raised, rounded border to the actinal surface. 
Width slightly exceeds the length. The surface is beset with scattered granules, similar to those of 
superomarginals but more numerous, and each plate is surrounded by a regular series of bead-like 
granules. A narrow zone along upper or lateral face of plate is usually free from scattered granules, 
and 1 or 2 spatulate pedicellarise usually take their place. Distal inferomarginal is diminutive. 
Abactinal surface is very slightly convex to plane, often depressed in interradial areas. On radial 
areas plates are regularly circular, or faintly hexagonal, fairly large, close-set, the spaces between 
them being occupied by papulae. The latter are absent from interradial areas, where the plates are 
less regular, usually hexagonal, sometimes quadrate or pentagonal in outline, and of less uniform size. 
All plates decrease in size toward the margin, and toward center of disk. The general surface of a 
plate is nearly flat, destitute of deciduous granules, but roughened by numerous minute bosses or low 
protuberances. Surrounding each plate, and occupying space between adjacent plates, is a peripheral 
series of flattened bead-like granules, with rounded or flattened tips. Numerous pedicellariae, similar 
to those of marginal plates, are present on abactinal surface. 
Adambulacral plates are about as wide as long, with straight furrow margin, but often with an 
angular outer margin. They are conspicuously smaller than the adjacent series of actinal intermediate 
plates. Armature as follows: (I) A furrow series of 7 (sometimes 6 in smaller specimens) stout, blunt 
spinelets, compressed, placed edgewise to furrow. They stand subparallel, and usually perpendicu- 
larly to actinal surface. (2) Following these, on the actinal surface, a longitudinal series of 3 short, 
blunt spinelets about two-thirds the length of furrow spinelets. Then comes another longitudinal 
irregular row of 3 or 4 blunt, conical granules, and on outer edge of the plate a series of slightly smaller 
granules 4 to 7 in number. The ambulacral furrow is very narrow, the furrow spines of the 2 sides 
interlocking. 
Actinal interradial areas paved with rather large plates, mostly irregularly 4-, 5-, and 6-sided. 
They are arranged in fairly definite series parallel to adambulacrals, and the plates diminish in size 
toward the margin, the largest plate being in the angle adjacent to mouth plates. All are covered 
with numerous, coarse, but not crowded, rounded or subconical granules, and a more or less definite 
peripheral series is distinguishable on each plate. A few plates toward the mouth angle bear 1 or 2 
two-jawed spatulate pedicellarite, similar to those on the marginal and abactinal plates. 
Mouth plates are plane, each with a straight free margin. Marginal spinelets, 7 or 8, are blunt, 
stout, and about as long as furrow spinelets of adambulacrals, of which series they are a simple, 
straight continuation. Most of the spinelets are 3- or 4-sided, and increase slightly in size as they 
approach the inner angle. On the actinal surface there is a row of 3 to 5 smaller, irregular, often 
pointed, thick spinelets parallel to furrow series, and a row of several low, rounded, or subconical 
granules along margin of medium suture and 3 or 4 along that edge of plate adjacent to first adam- 
bulacral plate. The outer end of the united pair of mouth plates is broadly truncate. Granules are 
conspicuously larger than those of the actinal intermediate plates. 
Madreporic body relatively larger than that of P. ammophilus, about the size of surrounding 
plates; subcircular; striations of medium coarseness, irregularly radiating. The body is surrounded 
by small flat granules, like rest of abactinal plates. 
Color in life, buff pink; in alcohol bleached yellowish to whitish. 
Variations: A small specimen (R=21 mm. ; r=12 mm. ) has the sides of the disk decidedly arcuate, 
the relation of the major to minor radius being as 1.75 to 1, instead of 1.44 to 1, as in the type. 
Superomarginals of young specimen encroach more upon abactinal area than do those of the adult. 
Localities: Type (no. 21163, U. S. National Museum) from station 3883, Pailolo Channel, between 
Maui and Molokai Islands, 277-284 fathoms, globigerina ooze; bottom temperature 45.2°. Taken also 
at the following stations: 3865, same locality, 256-283 fathoms, fine volcanic sand, rocks; 4082, north 
