REPORT ON THE ASTEROIDEA. 361 



tumid, or slope slightly at a high angle to the margin, in other words, nearly vertical. 

 Actinal surface nearly plaue, 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 striae upon its surface have 

 the appearance of more than usual regularity in their centrifugal radiation. 



Papulae 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 papilla?. 



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 149e. Off Cape Maclear, Kerguelen Island. January 21, 1874. 

 Depth 30 fathoms. 



Station 149h. 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 Porania 



(ZOOL. CHALL. EXP. PART LI. — 1888.) -t(j 



