THE STARFISHES OF THE HAWAIIAN ISLANDS. 
1023 
Genus PSILASTEROPSIS, new. 
Type Psilasteropsis eingulata, new species. 
Disk small; rays long, robust, and tapering to a pointed extremity. 
Marginal plates massive, conspicuously encroaching on both abactinal and actinal areas; slightly 
or strongly tumid. Surface of plates covered with squamules, becoming papilliform in groves between. 
Superomarginal plates devoid of large spines or tubercles; inferomarginals bearing a series of short 
tapering spines, disposed more or less obliquely and closely appressed to ray. 
Abactinal area covered with compact paxillse, composed of papilliform spinelets grouped in a 
coordinate bunch on a thick pedicel. Arranged more or less regularly in transverse rows at sides. 
Abactinal plates (bases of paxillse) roughly hexagonal, placed rather close together. Papulae 
conspicuous, arranged around each plate. They are scarce toward extremity of rays and center of 
disk. 
Actinal interradial areas small, with small intermediate plates which extend only about one-third 
the length of ray. Intermediate plates all bear groups of papilliform spinelets, which are sometimes 
grouped to form an incipient pedicellarian apparatus. 
Adambulacral plates massive. Armature consists of (1) a furrow series of numerous, rather 
delicate, subequal, long, uniform spinelets forming a regular, straight-edged comb; (2) on the actinal 
surface of the plate 2 or 3 irregular longitudinal series of shorter, cylindrical spinelets. These are 
sometimes grouped to form a conical pedicellarian apparatus on plates near base of rays. Tube feet 
without sucking disks, large, in 2 rows. 
Madreporic plate of medium size, situated rather nearer margin than midway between it and 
center of disk. 
A tiny pore, anal in position, is apparently present. Superambulacral plates present, well- 
developed. 
This genus is erected for the reception of a species which differs in several essential points from 
true Psilasler; namely, in the more massive and distinctly tumid marginal plates, very much reduced 
fasciolar channels, the more restricted actinal intermediate plates, which do not extend far along the 
ray, in the regular and more numerous furrow spines of the adambulacral plates, in the large paxillse 
which are tabulate, and which give to the abactinal surface a very characteristic appearance. In this 
genus should be ranked, also, Psilaster patagiatus Sladen, which, however, differs from eingulata in 
having incipient excavate pedicellarise on the superomarginals and in the armature of the mouth 
plates. The general facies of the two species is much alike. Mr. Sladen, in describing Psilaster 
1 patagiatus, expressed serious doubts as to the propriety of referring that species to the genus Psilaster, 
and now that a second, similar, well-marked form has been found on the opposite side of the globe, 
it becomes doubly necessary to segregate the forms. 
Psilasteropsis eingulata, new species. 
PI. Ill, figs. 2, 2 a-b; pi. VII, figs. 1, 2, 3; pi. vm, fig. 2. 
Rays 5. R=95 mm; r=18 mm. R=5 r+ . Breadth of ray near base (between second and third 
superomarginal plates) 18 mm. 
Rays long, fairly narrow at the base, gently and gradually tapering to an acute tip. Disk small. 
General form somewhat flat and depressed. Sides of ray nearly perpendicular. Abactinal surface 
plane; actinal nearly so. Interbrachial arcs acute but well rounded. 
Abactinal paxillar area is depressed slightly below the level of the superomarginal plates and 
extends to the tip of the arm, but is usually greatly reduced in width on the distal third of the ray, 
being only about as wide as the furrows between the superomarginals of that region. Width of paxil- 
lar area at base of ray (between second and third superomarginals) 12 mm. Paxillse are larger in the 
center of ray than on side, but are smaller in center of disk. They are subcircular in outline when 
regarded from above, short, composed of a short cylindrical basal ossicle surmounted by delicate 
cylindrical spinelets in a coordinated group. In the larger paxillse a peripheral circle of 15 to 25 spine- 
lets surrounds an irregular central group of about 15. Instead of flaring, the marginal row usually 
stands perpendicularly, or inclines inward against the central group, giving the paxillar crown a very 
compact appearance. Spaces between paxillse are conspicuous, allowing the small papulse to be clearly 
F. C. B. 1903, Pt. 3—17 
