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Show 222 MR. S. O. RIDLEY ON THE CORALLIID.E. [Feb. 7, C. secundum is no doubt in America, in company with the other specimens obtained at the same time by the United-States Exploring Expedition. The Red Coral (C. nobile) occurs in the Mediterranean, and among the islands (e. g. Cape-Verd Islands, see Wyville Thomson, Voy.' Challenger,' Atlantic, i. p. 70) lying off the N . W. coast of Africa; it occurs nowhere1 else, so far as I have been able to discover. C. secundum is recorded with doubt as from the Sandwich Islands; it was probably obtained in the Pacific Ocean at any rate ; C. johnsoni was obtained from Madeira. In the present paper is described a fourth species, and one which is probably not new, belonging to this remarkable and beautiful family: the one was obtained from the island of Mauritius, and is now in the collection at the British M u s e u m ; the other is stated to come from Japan, and will shortly be incorporated with the same collection. Arrangement of the Family.-The only attempt which has been made at classifying the species is that of Dr. Gray in a Note read before this Society, and published in its 'Proceedings' for 1867 (p. 125), and somewhat amplified in 'Catalogue of Lithophytes or Stony Corals' (1870), p. 22. Dr. Gray divided the family and the original single genus Corallium into 3 genera, based mainly on the distribution of the "polypes" (meaning polype-cells, verruca? of Verrill) on the branches, viz.:- (1) Corallium, with the verrucae slightly elevated from the cortex and scattered on all sides of the branches (inch C. nobile). (2) Pleurocorallium, branching in a single plane ; the verrucae slightly raised, confined to one surface, and mostly placed on small branches chiefly found near the edges of the main branches (inch C. secundum, Dana). (3) Hemicorallium. The verrucae prominent, all occurring on one side of the branches (inch C. johnsoni, Gray). With regard to this arrangment, it seems well to point out that the characters on which it is founded appeal entirely to the naked eye. In the allied members of the same group, the Alcyonaria, Prof. Kolliker (see 'Icones Histiologicae') and Verrill (see various papers in the Proc. Essex Institute, Trans. Connecticut Academy, American Journal of Science, &c.) have shown good reasons for the belief that the majority of those characters, such as colour, manner of branching, presence or absence of anastomosis between branches, to which alone those writers can appeal who do not make use of a microscope in their researches, must be regarded as usually of no more than secondary importance in the estimation of the mutual affinities of the different subdivisions and species of this group. From personal study I can testify to the truth of this principle in the case of the Melithaida, which are probably the nearest allies of this family. In them anastomosis of branches may be simply a varietal circumstance ; coloration of the internal parts is open to the same remark, and external coloration is far more frequently so ; the manner of branching is much the same in all ; so that, for classifi- 1 It is found fossil in the Upper Pliocene and Quaternary deposits of South Italy, cf. Seguenza, Atti Ac. Line. (3) Mem. sc. fis. mat. nat. iii. pp. 331, 373. |
