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Show 1884.] SPECIES O F OREASTER. 77 OREASTER DORSATUS. Pentaceros dorsatus, Perrier, Rev. Stell. p. 245 ; but substitute the following for the inexact synonymy there given :- 1753. Asterias dorsata1, Linnaeus, Mus. Tessin. p. 114, pi. ix. 2. 1758. Seba, Thesaurus, iii. pi. v. 7, 8, pi. vi. 1, 2. 1766. Asterias nodosa, Linnaeus, Syst. Nat. p. 1100 (pars). 1842. Oreaster clavatus, M.Tr. Syst. Ast. p. 49. 1864. Oreaster dorsatus, Liitken, Vidensk. Med. p. 161. This species has been so admirably diagnosed by Miiller and Troschel that had I not here the object of giving original and similarly constituted definitions of such species as I have seen, I should gladly content myself with referring the student to their description. R=2*2 r. Upper surface, in dried specimen, almost flat; arms not acutely pointed. Lophial line and spines distinct, the apical not especially prominent; spines developed within the apical region. About 12 supero- and 14 inferomarginal spines, the latter distally, but not proximally taking a share in the formation of the side of the arm. Both sets are provided with spines; on the upper plates these spines are of some size, and frequently two are developed ; these are set one above the other so as to lie at right angles to and not parallel with the long axis of the arm. Two spines are likewise often developed on the inferomarginal plates; these spines are sometimes of a fair size, but are frequently rather tubercular than spinous. Adambulacral spinulation diplacanthid ; three strong and often subequal spines in the inner, and one very stout, with rounded tip, in the outer row. The separate ventral ossicles are quite easily made out under the rather coarse granulation by which they are invested ; the row of ossicles running along the side of the adambulacral series is without spines, but those outside this, of which there are four in the proximal and two in the most distal region, are provided with one and sometimes with two rounded spinous projections. The upper, like the lower surface, is well provided with spines, and here again two are frequently found to be developed on the free surface of one and the same ossicle. The lophial ossicles are large ; as large indeed, if not larger than, the more proximal superomarginals ; 1 The only foundation for the statement of Miiller and Troschel, reiterated by Perrier, tbat in the Mus. Tessin. Linnaeus called this species A. stellata, is the fact that the word stellata is the first in the definition of the species. As the work is rare (the copy from which I took this note was one which I saw, by the kindness of Professor Lindstrom, in the admirable Library of the Royal Academy of Sciences at Stockholm), I think it well to give in full what Linnasus " Dorsata. Asterias stellata, radiis convexis lougitudinaliter elevatis. Tab. ix. fig. 2. Locus: India. ,.. . ,,. • u • J-I i ..- T Stella spithami diametro. Radii quinque, obtusi, versus basin dilatati, dorso admodum convexi, adspersi undique mucronibus obtusiusculis remotis. Subtus plana, adspersa punctis prominulis; rima cincta papillis subulatis, tenuissimis." |