ASTEEOIDEA OF H.M.8. ' CHALLENGEE ' EXPEDITION. 255 



series on the surface of the plate ; and these are succeeded by 8 

 or 9 pairs of short flat spines, closely placed and occupying the 

 middle portion of the surface, on which they stand perpendicular ; 

 and the outer part of the plate carries 3 or 4 spines in single line 

 directed outward, their length and robustness increasing as they 

 recede from the mouth. The next adambulacral plate to the 

 mouth-plates is narrow, and the spines thereon are small, uniform, 

 and arranged in two single lineal series apposed to one another. 



The paxillge of the dorsal area are large and form a compact 

 surface. Each consists of four or five short granulif orm spinelets 

 in the centre of the tabulum surrounded by a circle of a dozen or 

 more short delicate obtuse spinelets, the central four having a 

 rather isolated appearance within the circle. A very large conical 

 prominence is present in the centre of the disk. The madrepori- 

 form body is obscured by paxillse. 



The ambulacral sucker-feet are small and terminate in a point, 

 which is tipped with black and gives a very singular appearance 

 to the species. 



Colour, in alcohol, yellowish grey. 



Station 192. Lat. 5° 42' S., long. 132° 25' E. Noon. Depth 

 129 fms. ; mud. 



AsTEOPECTEN JAPONicus, Muller Sf Troschel. 



Station. Off Yokohama, Japan. Depth 8-14 fms. ; 5-25 fms. 



Station 233 a. Kobi, Japan. Lat. 34= 35' N., long. 135° 10' E. 

 Depth 8-50 fms. ; mud, sand. 



Station 233 b. Lat. 34° 20' N., long. 133° 35' E. Depth 

 15 fms. ; mud. 



ASTEOPEOTEN IMBELLIS, n. Sp. 



Eays five. i2<3'5r; -S=24 millim., r=l millim. Eays 

 rather narrow, especially on the outer part, tapering continuously 

 from the base to the extremity. Breadth of a ray at the base 

 about 7 millim. Interbrachial angles subacute. 



Supero-marginal plates 18 in number from the interbrachial 

 angle to the tip, about as broad as high, but higher in the inner 

 part of the ray. The plates are slightly tumid, and form a well- 

 rounded margin to the ray. The surface of the plates is covered 

 with very fine, closely-placed, papillif orm granules ; and the 8 or 

 9 innermost supero-marginal plates bear a small, delicate, sharply 

 pointed spinelet about equal in length to the length of the plate, 

 and placed near the middle of the dorsal portion of the plate. The 



LINJS". JOFEN. — ZOOLOGY, YOL. XYII. 19 



