292 THE VOYACxE OF H.M.S. CHALLENGER. 



52" 4' 0" S., long. 71° 22' 0" E. Depth 150 fathoms. Coarse gravel. Bottom tem- 

 perature 35°'2 Fahr. ; surface temperature 37°"5 Fahr. 



Station 151. Off Heard Island. February 7, 1874. Lat. 52° 59' 30" S., long. 73° 

 33' 30" E. Depth 75 fathoms. Volcanic mud. Surface temperature 36°-2 Fahr. 



Remarks. — This species is readily recognised by the length of the rays, by their 

 narrow and tapering form, by the flexibility of the abactinal surface, and by the uniform 

 low granulation, which in no case approaches the character of spines. 



3. Gnathaster pilulatus, n. sp. (PI. LVII. figs. 5-7). 



Rays five. R = 42 mm. ; r= 21-23 mm. R = 2 r approximately. Breadth of a ray 

 at the base, 24 mm. 



General form depressed, slightly inflated over the radial areas ; marginal contour 

 stellato-pentagonal. Pays short and triangular in form, wide at the base, tapering con- 

 tinuously to the extremity, with straight sides. Interbrachial arcs very wide, distinctly 

 angular at the summit. 



The whole abactinal paxillar area is covered with comparatively large, short-stalked, 

 capitate, well-spaced paxillae, the crown of which consists of a dozen or more low, truncate, 

 close-fitting, prismatic granules, surrounded by a number of small papilliform spinelets, 

 the whole forming a compact, smooth-surfaced, hemispherical knob, which has the appear- 

 ance to the naked eye of a well-defined tubercle. The paxillae are widely spaced, and the 

 papulae, which are large, have the appearance of emerging from the angles of a hexagonal 

 plate. The arrangement of the paxillae is in regular oblique transverse lines, and the 

 paxillae diminish gradually in size as they recede from the median line of the ray and 

 approach the margin. In a large specimen, which has the radial inflation fairly well 

 developed, there is a distinct depression or channel traversing the median interradial 

 line. 



The supero-marginal plates are small and quadrangular, distinctly broader than long, 

 the sutures between adjacent plates being broad and well-defined. The supero-marginal 

 plates are nineteen in number from the median interradial line to the extremity ; and 

 there is also an odd cuneiform plate in the median interradial line. The surface of the 

 plates is slightly convex, and covered with low, uniformly truncate, subprismatic 

 granules. 



The infero-marginal plates correspond in number and also more or less in size to the 

 superior series, but their armature is quite different, and causes this series of plates to 

 appear much more prominent than the superior series, leading at first sight to the sup- 

 position that they (the infero-marginal plates) alone form the outer margin. They are 

 covered with small, robust, conical-pointed, papilliform spinelets, their disposition giving a 

 bristling or tufted appearance to the plates, in strong contrast to the low and uniformly 



