ao 
REPORT ON THE ASTEROIDEA. 361 
tumid, or slope slightly at a high angle to the margin, in other words, nearly vertical. 
Actinal surface nearly plane, the intermediate areas slightly tumid between the ambulacral 
furrows and the margin. Seen on the actinal side, the comparatively great length of the 
rays for this genus is especially noticeable. The whole surface of the starfish is covered 
with a thick leathery investing membrane. No spines or tubercles of any kind are present 
on the abactinal surface. 
The marginal plates bear a single, short, flat, truncate spinelet, and occasionally two 
are present. These are directed horizontally. Marginal spines are not present on the 
outer part of the ray, and extend only a short distance beyond the disk proper. 
The armature of the adambulacral plates consists of two spines,—one on the furrow 
margin, which is robust at the base and tapers to a point; the other on the actinal 
surface of the plate, which is rather longer and much larger than the furrow spine, is 
flat, abruptly truncate at the tip, and often fimbriate there, also often more or less gouge- 
shaped, with the groove on the outer side. Occasionally a supplementary outer spine is 
present on the median or outer part of the furrow. 
On the actinal surface the membrane is traversed by channels which run from the 
adambulacral plates to the margin; the marginal spines appearing as if placed one at the 
end of each band thus marked off by the furrow-like channels. 
The madreporiform body, which is rather large and suboval, is situated approximately 
midway between the centre of the disk and the margin. The strize upon its surface have 
the appearance of more than usual regularity in their centrifugal radiation. 
Papule numerous and generally distributed on the abactinal surface, excepting in the 
median interradial areas, and perhaps also, but less distinctly, on the median radial line 
of the rays. 
The anal aperture is subcentral and closed by numerous comparatively robust papillae. 
The ambulacral tube-feet are quadriserial in the median portion of the ambulacral 
furrow. 
Colour in alcohol, a yellowish white, often with a more or less brown shade. 
Localities.—Station 149. Off Cape Maclear, Kerguelen Island. January 21, 1874. 
Depth 30 fathoms. 
Station 149m. Off Cumberland Bay, Kerguelen Island. January 29,1874. Depth 
127 fathoms. Surface temperature 39°°8. 
Remarks.—This form is very nearly allied to Porania antarctica, but is distinguished 
by the total absence of any spines or tubercles whatever on the abactinal surface. The 
rays are broad at their base, and less pronounced where they spring from the disk, having in 
consequence less trace of any interradial constriction or depression. No marginal spines 
are present on the outer part of the ray of Porania glaber, whereas they are continuous to 
the extremity in Porania antarctica. The disproportion in length between the inner and 
outer spine on the adambulacral plates is not so great in Porania glaber as in Porama 
(ZOOL. CHALL. EXP.—PART LI.—1888.) 46 
