REPORT ON THE ASTEROIDEA. 229 



papilliform along the transverse margins, thus emphasising the suture. No spines are 

 borne on the supero-marginal plates. 



The infero-marginal plates correspond to the superior series, and their breadth is 

 greater than either the height or the length ; their surface is covered with granules 

 apparently similar to those above described and of equal size, but which have a tendency 

 to become scutiform as they approach the end of the plate adjacent to the adambulacral 

 plates. Their length and posture is such that they have quite the appearance of granules, 

 and their squamous character is only made out after careful examination. Each infero- 

 margiual plate bears normally a single small spinelet, which is short, tapering, slightly 

 compressed, and appressed to the side of the ray. It is situated at the extreme margin of 

 the ray, on the rounding which unites the actinal and lateral areas of the plate, and stands 

 close to the aboral margin of the plate. On two or three of the plates in the interbrachial 

 arc a second and similar spine may be present, placed midway between the lateral spine 

 and the inner end of the plate ; and in very rare instances there may be one or even two 

 small spines above the lateral spine, between it and the abactinal end of the plate, these 

 spines being always at the aboral margin of the plate. 



The adambulacral plates are large, with a prominent angular margin towards the 

 furrow. Their armature consists of an inner or furrow series of seven or eight short, 

 delicate, cylindrical, equal . spinelets, encased in membrane, but apparently without any 

 saccular developments. On the actinal surface of the plate are one or two longitudinal series 

 of three or four equal spines, slightly shorter than the inner series. There is frequently, 

 however, irregularity in the disposition of these spinelets ; and the whole armature usually 

 forms a wedge-shaped group, the arrangement of which is difficult to formulate. 



The mouth-plates are elongate and very narrow ; their armature consists of a marginal 

 series of sixteen to eighteen short, cylindrical, obtusely rounded or subclavate papillae 

 on each plate, which increase slightly in length as they approach the anterior end. The 

 two innermost are longer and much more robust than the rest. On the actinal surface of 

 the plate is a single uniserial row of low, broad, round-topped and slightly compressed 

 papillse, about sixteen or eighteen in each series. These stand vertical, and the marginal 

 series are closely appressed to their sides. 



The actinal intermediate plates, though confined to a very small area in the inter- 

 radial region, extend far along the ray. Those near the adambulacral plates bear 

 spinelets which are indistinguishable from the adambulacral armature, whilst those near 

 the marginal plates, in the interradial area at least, become somewhat more papilliform, 

 and though maintaining a strictly spinulate character, approach in a certain degree the 

 squamulate form of the covering of the marginal plates. All these spinelets are covered 

 with thin membrane, which has to some extent the peculiar fibrillar or matted character 

 sometimes noticed in the Northern form, and many of the spinelets have the same 

 agglomerated appearance suggestive of entangled foreign matter or tissue. 



