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Show 1871.] MR. W. S. KENT ON NEW MADREPORES. 277 ccenenchyma, indicate its true position among the representatives of the genus Amphihelia of the same author, to which genus I here refer it while proposing the following more exhaustive specific diagnosis:- Corallum arborescent, irregularly branching, subflabellate. Ccenenchyma faintly striate, frequently coalescing, somewhat fistulose; greatly developed in the trunk and main branches, but almost entirely wanting in the ultimate ramifications. Calices infundi-buliform, increasing by alternate distal gemmation, two gemmae, however, occasionally springing, as in Cyathohelia, opposite each other from the margin of the same calice. Septa 24 in number, forming three complete cycles ; the primaries more exsert than the secondaries, and the latter slightly more so than the tertiaries, projecting but little into the calicular fossa, to which they consequently give the " internal striate" appearance observed by Lamarck. Costa, only visible superiorly. Height of corallum several inches. Diameter of calices y1^ inch. Hab. Formosa, Indian seas, B.M. STENOHELIA MADERENSIS, nobis. (Plate XXIV. figs. 3, 3 a, b, ci) Allopora maderensis, J. Y. Johnston, Proc. Zool. Soc. 1862, p. 196, figs. 1,2, 3. Stenohelia, maderensis, W . S. Kent, Ann. & Mag. Nat. Hist. v. p. 120, 1870. I avail myself of the opportunity of giving here an illustration of this interesting species, first introduced by Mr. Johnston, but whose characters and structure are by no means satisfactorily explained or displayed in the description and figures accompanying his communication. Since the publication of my paper above quoted, in which I make this form the type of a new genus, I have, through the kind courtesy of Prof. D u Bocage, examined additional specimens belonging to this same species contained in the Lisbon-Museum collection, obtained from the Cape-Verde Islands, and having the ampullae, present in the British-Museum example, still more highly developed. A fragment in illustration of this is represented at Plate XXIV. fig. 3 a. STYLASTER AMPHIHELOIDES, n. sp. (Plate XXIV. figs. 1, 1 a, b, c.) Corallum branching, subflabellate; basal ccenenchyma often fistulose and coalescing, its surface smooth. Calices increasing by alternate distal gemmation; calicular fossa deep. Columella styliform, echinate, deeply immersed. Septa even, twelve to sixteen in number, projecting but little into the calicular fossa, often coalescing laterally, and so forming an inner tube, and giving tbe interseptal chambers a punctate appearance, as in S. erubescens (Pourtales) and various species of Allopora. Ampullae rudimentary, represented by a few raised points scattered irregularly over the surface of the ccenenchyma, but more particularly in the neighbourhood of the ultimate ramifications. |
