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Show 122 PROF. F. J. BELL ON N E W [Jan. 17, rounded at their tips. Madreporic plate almost subcentral. The integument is thick, and has a peculiar clamminess; and the spines developed on the surface are rather scale-like rounded processes, ornamented with a radial striation; of these an irregular series extends along the median dorsal line of each ray ; towards the extremity of the ray the scales become a little thinner and longer, or, in other words, more spinous ; the striation m a y still be detected on their tips. While at this end they are somewhat scattered, they are more numerous at the base of the arm, where also they are larger. Passing into the disk a complete circlet is made by these processes, the aggregation at the base of each radial series being brought into connexion with its fellows by interradial aggregations. In this way a rather broad though somewhat feebly indicated circlet of modified spines lies around the centre of the disk ; a few similar spines are to be found in the central space. In the middle of one of the interradial aggregations there is placed the madreporic plate, which thus comes to be surrounded by a circlet of spines. On the arms three rows of pore-areas may be made out on either side of the median row of spines, which are the only spinous processes that are developed on the abactinal surface. The marginal spines, short and blunt and pretty regularly arranged, have an appearance not unlike that presented by the jaw of a Cyclodus. Between them and the adambulacral spines there is a bare space, which, in this spirit-specimen, is narrow and groove-like. The whole creature is of a yellowish-white hue ; and the suckers are little darker than the rest of the body. A single specimen. The only indication of its habitat is the fact that it was collected during the voyage of the ' Erebus' and ' Terror.' CRIBRELLA MINUTA, n. sp. (Plate VI. fig. 2.) R = 18; r = 6*5 Arms five, 6 millim. wide at their base, and somewhat rapidly diminishing in breadth. The abactinal surface plain, and similar for its whole extent. The adambulacral spines fringing the groove are arranged in a single row ; there is generally one for each plate; they are of a fair size, and are distinctly separated from one another. Externally to these there is a series of transverse rows, containing at least three or four spines, and sometimes having them arranged in double order. Beyond these, and separated from them by a more or less distinct longitudinal groove, is a longitudinal row of closely packed spines. Externally to this there are a number of combs of spines set transversely, which occupy the edge of the actinal surface of the ray. The next series of spines is not so regularly arranged, and leads to the irregular disposition of spiniferous ossicles which obtains on the abactinal surface. The madreporic plate is small, obscure, and marginal. No pedicellariae detected. The colour of the single example (which has been in spirit for more than twenty-five years) is dead white. Ecuador (Haslar collection, J. O. Goodridge, Esq., R.N.). |