OCR Text |
Show 70 PROF. F. J. BELL ON THE [Feb. 19, In the outer row there are ordinarily two very well-developed spines, though, here and there, three are to be detected. None of the ventral plates bear spines ; some of the granules on the more proximal of them are larger than the rest, and form very distinct aggregates. The valvular pedicellaria; scattered among them are small and not very numerous. The poriferous areae on the dorsal surface are arranged in three very regular rows along either side of the arms ; the areae are not very large, and the pores are not numerous. The granules on the upper are larger than those on the ventral surface, and have no pedicellariae scattered among them. Towards the end of the arm the lophial ossicles may project a little, but they never develop spines. Madreporic plate set just between two of the apical spines, irregularly lozenge-shaped, not large. The integument is much thicker than in most species of the genus, . and the specimen has the dead-white colour which we can imagine 0. chinensis would have had had it been preserved in spirit. Measurements : - R = l 16 ; r = 3 5 ; greatest breadth of arm 28. Hab. Billiton. OREASTER NODOSUS. Pentaceros turritus, Perrier, Rev. Stel. p. 240. Asterias nodosa, Linnaeus, Syst. Nat. ed. xii. p. 1100 (pars). Prof. Perrier prefers Linck's name to that of Linnaeus, whom, indeed, he abstains from directly quoting, his only reference being to Gmelin's edition of the ' Systema Naturae.' R=2*5 r to 3 r. Disk considerably elongated ; arms long, rather narrow. Lophial line well marked, with prominent rounded projections ; the apical spines very prominent, and a central one typically developed. About 30 superomarginal, and one or two more inferomarginal . plates ; both sets obscure, and without any spines, the lower altogether confined to the actinal side. Adambulacral spinulation diplacanthid ; ordinarily seven spines in the inner row, of which two or three in the middle are distinctly longer than those at their sides. In the outer row three spines, about twice as stout as those of the inner row ; between the two rows there stands a well-developed forcipiform pedicellaria. The separate ventral ossicles are a good deal obscured by the coarse granulation with which they are covered; the only region in which there can be said to be a distinctly serial disposition of the Slates is that which extends along the side of the ambulacral groove. lany of the investing granules are more than a millimetre in length along their longest axis, and the sessile valvular pedicellariae are very numerously represented. A similar coarse granulation is found on the marginal plates ; but any resemblance to O. lincki is opposed by the development of a very large number of pedicellariae '. The upper surface might almost be said to be one mass of pedi- 1 Have we not here another example of the kind of balance that obtains between the development of spines and of pedicellaria: ? Cf. the case of Asterias glacialis, Zool. Anz. 1882, p. 283. |