REPORT ON THE ASTEROIDEA. 199 



The paxillas of the abactinal area are small and compact, and composed of six to nine 

 spinelets, of which one is central. The spinelets, which are short and robust, are directed 

 upward, and their radiation aparb is very slight. No definite order is maintained in the 

 arrangement of the paxillae. The papulae are small, and dark brown or almost black in 

 colour ; and a broad space occurs along the median line of the ray in which none are 

 present. In the centre of the disk there is a large and conspicuous conical prominence, 

 upon and in the neighbourhood of which tbe'paxillae are greatly reduced in size. 



The supero-marginal plates, which are twenty-two in number from the median inter- 

 radial line to the extremity, are higher than broad along the inner half of the ray, but 

 broader than high on the outer portion. Each plate, excepting two or three in the inter- 

 brachial arc and a few at the extremity, bears two small, conical, sharply pointed spines. 

 The inner series are placed close to the inner edge of the plates, and are continuous from 

 the arm-angle until near the tip, decreasing in size as they proceed outward, until they 

 disappear altogether. The outer series are slightly larger, and are placed at the extreme 

 edge of the plates on the curvature where the abactinal and lateral superficies unite ; they 

 are continuous throughout the ray, excepting the innermost plate on each side the median 

 interradial line. 



The infero-marginal plates are higher than broad, and flush with the superior series. 

 Each plate bears a single lateral spine, which is short, tapering continuously from base to 

 tip, sharply pointed and slightly compressed. On the inner half of the ray, two similar 

 and slightly smaller spines are situated on the median line of the plate — one, which is the 

 smallest, not far from the inner edge of the plate adjoining the adambulacral plates, and 

 the other about midway between this spine and the lateral spine, the three forming a lineal 

 series transverse in relation to the direction of the ray. On the outer portion of the ray 

 the inner spine is aborted or indistinguishable from the scmamules of the plate. When 

 the side or lateral wall of the ray is placed in direct view, the above-mentioned spines of 

 the infero-marginal plates are all visible, and they, together with the spinelets of the 

 supero-marginal plates, appear to form a continuous vertical series. The lateral spine is 

 very little, if at all, longer than the outer spine on the supero-marginal plate, and all these 

 spines stand at an angle to the superficies of the plate, and are directed upward and out- 

 ward. Very short, widely spaced, papilliforuf squamules are distributed over the surface 

 of the infero-marginal plates, and the granulation of the supero-marginal series partakes 

 of the same character, and is indistinguishable at the junction of the plates. 



The armature of the adambulacral plates consists of short, robust, subpapilliform 

 spinelets, which do not taper, and stand more or less perpendicular to the surface of the 

 plate. The furrow series consists of four or five spines, and their base line forms a slight 

 angle projecting into the furrow ; the middle spinelets are a shade larger and more robust 

 than the others. The actinal surface of the plate behind the furrow series is occupied by 

 spinelets which are little more than elongate papillae ; they' are small, stumpy, covered 



