ASTEEOIDEA OF H.M.S. ' CHALLENGER ' EXPEDITION. 193 



dendriform in appearance, fairly well spaced. The s^piracula are 

 rather large, not numerous, and are irregularly placed. 



Ambulacral furrows narrow, uniform in breadth till near the 

 extremity, not petaloid. Ambulacral suckers in regular simple 

 pairs. Ambulacral spinelets short and rather robust, 3 to 4 iu 

 each comb, 3 only on the outer part of the ray. Innermost spine 

 nearly as long as the others, or, if a small inner one is present, it is 

 so aborted as to be invisible without dissection. "Web remarkably 

 thick and fleshy, subsaccular over the spinelets, passing off from 

 the outermost spine with a long gentle sweep far out on to the 

 lateral fringe. 



Mouth-plates each bear on their margin about three rather 

 short, robust mouth-spines webbed together. Secondary super- 

 ficial mouth-spines one on each plate, perpendicular to the plane, 

 longer than any of the other spines, exceedingly thick, trian- 

 gular, translucent, sharply pointed, and covered with a thick 

 fleshy investment. 



Aperture-pap ill se large, prominent, subtriaugular. Actino- 

 lateral spines directed horizontally, comparatively long, especi- 

 ally in the interbrachial space. Web rather thick and fibrous. 



Colour, in alcohol, greyish white. 



Station 150. Lat. 52° 4' S., long. 71° 22' E. Depth 150 fms. ; 

 bottom temperature 1°'8 C. ; rock. 



Pteeastee stellieee, n. sp. 



Marginal contour stellato-pentagonoid, interradial angles 

 slightly indented, the minor radial proportion being 67'6 per 

 cent.; i2=34 millim., r = 23 millim. 



Hadii very broad at the base, and tapering to a fine extremity, 

 which is slightly recurved, margins of the rays not curved out- 

 ward. Dorsal surface depressed and flatly convex. Lateral fringe 

 scarcely extending beyond the margin. Actinal surface flat. 



Supradorsal membrane rather thick, regularly papillose in ap- 

 pearance, not reticulated, composed of closely interlacing fibrous 

 tissue. Paxillse numerous and closely placed, with crowns of 

 usually six spinelets radiating round a central one ; expansion of 

 spinelets shght, all uniformly protuberant. Tlie tips of the 

 spinelets elevate the membrane into little conical papilh-e, which, 

 in consequence of the regularity of the crowns of the paxilla>, 

 have the appearance of forming six-rayed stars with a central 

 papilla, raised slightly in relief above the general superficies. 



