ASTEEOiDEA 01^ lE.JJ.S. ' CIIALLENGEll ' £X1>EDIXI0N. 197 



are angular and not rounded ; outline of the rays graccfally curved 

 outwards. The lesser radius in the proportion of 59'5 per cent. ; 

 ii=47 uiillim., /•=28 millim. Dorsal profile moderately high 

 and rounded, tapering gradually to the extremity of the rays, 

 which are slightly upturned and expose the ambulacral furrow on 

 the dorsal area. Actinal surface flat. 



Supradorsal membrane very regularly and uniformly reticu- 

 lated. The paxillsD have long pedicels, and bear a crown of about 

 15 spiuelets, nearly as long as the pedicel. The central spinelet 

 is very niucb more robust and longer than any of the rest, and 

 stands perpendicular, rising in the centre of the mesh, wliilst the 

 others, which are slender and delicate, radiate round it and out- 

 wards to the fibrous bands that form the outline of the mesh. 

 The median spinelet is much more prominent than any of the 

 others ; and the thick fleshy cap formed upon it by the dorsal 

 membrane- imparts a very conspicuous papillate appearance to the 

 Starfish, assuming in large old specimens almost a semituberculate 

 character of great regularity and evenness of disposition. In 

 large, fully-grown specimens the whole membrane becomes very 

 thick and wrinkly, rendering it difficult to trace the radiating 

 bauds ; in moderate-sized specimens, however, they may be clearly 

 distinguished without removing the epidermis. From the central 

 spinelet 6 to 8 secondary muscular fibres radiate up to the main 

 fibres of the mesh ; they are o£ considerable thickness, and leave 

 only narrow interspaces, in which four or five small spiracula 

 occur. 



Ambulacral furrows very broad and petaloid in outline, with 

 sucker-feet arranged in quadruple series. Transverse combs of 

 ambulacral spines numerous and closely placed, with five mo- 

 derately long and robust spines, the uniting web being thick, 

 fleshy, and with long saccular prolongations extending beyond 

 the tips of the spines. The ambulacral spinelets are nearly equal 

 in length, except the innermost, which is shorter and more deli- 

 cate. Each alternate row is somewhat refilled from the furrow- 

 margin ; and in these combs the innermost sj^inelet is very much 

 smaller than its companions, in some cases almost aborted ; and 

 this spine is usually placed rather in advance of its row. 



Mouth-plates with long mouth-spines, 4 on each plate, all the 

 eight webbed together, not radiating apart, but forming a narrow 

 scoop-like fan, the inner three spines on each plate about equal 

 in length, the outermost spine very small and short. The secon- 



