REPORT ON THE ASTEROIDEA. 7 
34° 8’0”S., long. 152° 0’ 0” E. Depth 950 fathoms. Green mud. Bottom tempera- 
ture 36°°5 Fahr.; surface temperature 69°°5 Fahr. 
Remarks.—This is a very characteristic form, and distinguished from all other species 
by the small marginal plates, the well-developed infero-marginal spines, the conical 
tubercle on the supero-marginal plates, the conically-pointed granulation of the marginal 
plates, and the simple radiating paxille. 
5. Plutonaster notatus, n. sp. (Pl. XIV. figs. 6 and 7; Pl. XV. figs. 5 and 6). 
Rays five. R=31'5 mm.; r=10°75 mm. R<3,r. Breadth of a ray at the fifth 
supero-marginal plate, 5-5 mm.; midway along the ray, 4°5 mm. 
Rays short, very narrow, and slightly tapering; the wide and open interbrachial arcs 
emphasising their narrowness, as well as the pentagonal character of the disk from whence 
they proceed. Nearly square in section, with the angles slightly rounded. Disk com- 
paratively large. Abactinal surface of the disk slightly convex and inflated; that of the 
rays being flat. Actinal surface of the disk very slightly convex, subplane along the 
rays. 
The abactinal surface of the disk and rays is covered with numerous small paxilla, 
composed of short, cylindrical, obtusely tipped, equal spinelets, standing upright and 
forming compact little groups of uniform height, with seven to fifteen spinelets in each, 
two to four being central and usually slightly more robust than the others. Though 
crowded, the paxillze are so spaced that each remains distinct; upon the central area of 
the disk no order of arrangement is discernible, but near the marginal plates they are dis- 
posed in lineal series running towards the marginal plates. The series on each side of 
the median interradial line are parallel thereto; and as each succeeding series converges 
slightly, their position at the base of the ray is obliquely transverse to its axis; in other 
words, if the lines of these lineal series were produced, they would meet at a common point 
outside the margin in the prolongation of the median interradial line. This arrangement 
does not extend beyond the base of the rays; outward along the rays the paxille present 
no definite order of arrangement, nor yet upon the median radial line throughout, nor 
on the whole central area of the disk, as above noticed. No pedicellariz are present. 
The supero-marginal plates, twenty-two to twenty-four in number from the median 
interradial line to the extremity, are small, but form a distinct and recular border to the 
disk and rays. When viewed from above their breadth on the abactinal surface is slightly 
greater than their length; and when viewed laterally the height is subequal to the length 
along the greater portion of the ray, but increases in the interbrachial arc, where the 
plates have asmaller abactinal bending. Midway along the ray, the breadth of the supero- 
marginal plates is nearly as great as the width of the paxillar area. The union of the 
abactinal and lateral planes of the plates is well rounded. The supero-marginal plates 
bear no spines, but their surface is covered with tolerably large, uniform, hemispherical, 
(ZOOL, CHALL, EXP.—PART LI.—1887.) 13 
