REPORT ON THE ASTEROIDEA, 483 
rendering them inconspicuous; they have, however, the peculiarity of closing the space 
between their own and the next aboral comb at the margin of the furrow. The aperture- 
papille are small and sublanceolate in form, hidden in the general membrane, excepting 
their adoral side, which alone is free, and closes the aperture, shutting close up to the 
next aboral actino-lateral spine. 
The mouth and parts surrounding it are much sunken—a feature further emphasised 
by the deep wall of the continuous marginal fringe. The mouth-plates are elongate, with 
their aboral extremities produced into a rather prominent peak, suggestive of that in 
Hymenaster. About five mouth-spines are borne on the outer margin of each plate, the 
innermost much longer and more robust than the others, all webbed together and forming 
an elegant marginal comb conformable to the contour of the plate. The innermost spines 
of the two adjoining plates stand close together, but are not united by web. On the 
superficies of each plate, and nearer the mouth than midway, is a long, robust, cylindrical, 
rapidly tapering secondary spine, standing isolate and perpendicular, covered with mem- 
brane, but with no web-attachments. 
The actino-lateral spines are short and robust, not more than one-third longer than the 
outermost spine on the adambulacral plates, and tapering only very slightly. They are 
united by a close fibrous web, the margin of which and the tips of the spines (as well as the 
tips of the spinelets in the transverse adambulacral combs) are tipped with dark purple. The 
lateral fringe thus formed stands perpendicular on the margin of the furrow; and the spines 
comprising it would at first sight be thought to belong to the comb-series. The fringe of 
the adjacent sides of two neighbouring rays is merged together at their adoral extremity, 
forming a continuous fringe, which runs close past the aboral.end of the mouth-plates. 
Localities.—Station 189. In the Arafura Sea. September 11,1874. Lat. 9° 36’0”S., 
long. 137° 50’ 0” E. Depth 25 fathoms. Green mud. Surface temperature 79°0 Fahr. 
Station 187. Off Booby Island, Torres Strait. September 9, 1874. Lat. 10° 36’ 0” 
S., long. 141° 55’0” E. Depth 6 fathoms. Coral mud. Surface temperature 77°°7 Fahr. 
Remarks.—This remarkably handsome form may be distinguished at the first glance 
from all other species. In fact the superficial differences are so striking that I was at first 
disposed to accord it subgeneric rank; the structure of the supradorsal membrane, of the 
adambulacral armature, and of the actino-lateral fringe appearing to justify that step. 
Further study has, however, scarcely borne out the morphological importance which I was 
inclined to place upon these structures, and I now merely mention the circumstance as 
indicative of the characters by which the species may be readily distinguished. 
Genus Marsipaster, Sladen. 
Marsipaster, Sladen, Journ. Linn. Soc. Lond. (Zool.), 1882, vol. xvi. p. 202. 
Form depressed. Marginal contour pentagonoid. Abactinal area flatly convex. 
Actinal area plane. 
