REPOKT ON THE ASTEROIDEA 373 



The supero-marginal plates, which are nine ^or ten in number, counting from the 

 median interradial line to the extremity, alternate more or less with the inferior series. 

 They are covered with spinelets exactly similar to those on the abactinal plates, which 

 present a more or less tufted character, and thus define the separate plates. These plates 

 are vertical in the lateral wall, and are rounded on the abactinal surface, to which they 

 form a distinct margin when the starfish is viewed from above. 



The infero-marginal plates, which are nine or ten in number counting from the median 

 interradial line to the extremity, are large and distinct, their height in the vertical lateral 

 wall being nearly equal to, or even slightly greater than, their breadth on the actinal 

 surface. They are covered with spines similar to those above described, but which are 

 larger, longer, and more robust at the junction of the lateral and actinal areas of the plate, 

 thus forming a slightly more prominent tuft at the actinal margin of the test. On the 

 actinal area of the plate the spinelets are more widely spaced than elsewhere. The infero- 

 marginal plates are separated on the actinal surface by distinct channels. 



The adambulacral plates are broader than long ; their armature consists of : — (1.) Two 

 spines on the furrow margin, which stand side by side, are sbghtly divergent, and directed 

 over the furrow, but become oblique on the outer part of the ray and finally stand one 

 behind the other in series with the actinal spines about to be described ; these spinelets 

 are short, equal, tapering, and covered with membrane which is thick at the base. (2.) On 

 the actinal surface of the plate is a transverse series of three short, robust, skin-covered 

 spinelets, which radiate slightly apart in the plane of the direction of the series : these 

 spinelets may be subequal or the outermost may be rather smaller, or one of the other two 

 rather larger than the companion spinelets. 



The mouth-plates are small and have a marginal series of five mouth-spines on each 

 plate, the innermost two of which are a little larger than the rest. On the actinal surface 

 of each plate is a secondary series of two or three spines, two being large and regular. 



The actinal interradial areas are occupied by regularly arranged intermediate plates, 

 the innermost series extending far along the ray. The plates bear numerous, small, taper- 

 ing spinelets which have a tufted appearance in their disposition ; and one or two of the 

 central spinelets in a group may be a little larger and more robust than the others. The 

 tufts or groups are well spaced. The plates are indicated only by the tufts of spinelets, 

 their outline being indistinguishable in consequence of the thick investing membrane 

 under which the plates are hidden. 



The madreporiform body, which is small and circular, is situated rather nearer the 

 centre of the disk than midway between that point and the margin. 



The anal aperture is subcentral or slightly excentric, and, being surrounded by spinelets, 

 is only distinguishable with difficulty. 



The ambulacral tube-feet have sucker disks. 



Colour in alcohol, a bleached yellowish white. 



