Recent Poritidae, and the Position of the Family in the Madreporarian System.

Abstract

Summary. The foregoing pages contain a preliminary instalment to a revision of the classification of the Madreporaria by Milne-Edwards and Haime, which has been rendered necessary by recent advances in our knowledge of the morphology of the coral-skeleton. The object of the paper is to record the results, obtained during my work of cataloguing the specimens in the Natural History Museum, as to the position of Forties among the Madreporaria. A brief sketch of the history of the question led to a review of the present situation, in which the fundamental theory on which the existing system of classification which we owe to Milne-Edwards and Haiine rests was criticised in the light of recent research. This criticism entailed a re-statement, with slight amplification, of the author's phylogenetic scheme, along the lines of which it is maintained the classification of the Stony Corals will have, for the future, to proceed, i. e. until it is again sujjerseded by further advances in morphological science. The chief new points of interest with regard to this scheme related, (1) to the origin of septa; (2) to the various possible methods in which the primitive external epithecal cup may have been flattened and become replaced by an infernal skeleton. This last discussion brought us naturally to the object of the paper, viz., to enquire along what lines of development Porites obtained its peculiar internal and so-called “trabecular” skeleton. The conclusions arrived at were: – 1 The “trabecular” septum is only a misleading name for perforated lamellate septum. 2 The Poritid skeleton can be explained as an immature Madreporid skeleton, arrested in its growth by very early budding. 3 As this may have happened more than once, Porites may be polyphyletic in origin. The paper concludes with a brief discussion of the various genera which have been from time to time united with Porites in the same family or else separated from it as generically distinct. The revision suggested leaves the family Poritidae as Dana left it, with only two genera, Porites and Goniopora,–Porites enlarged by the absorption of Synaraea, Napopora, Neoporites, and Cosmoporites, and Goniopora also enlarged by the merging with it of Rhodaraea and Tiohopora. My best thanks are due to my friend Prof. F Jeffrey Bell for much kindly assistance, and for the warm interest he has taken in these investigations, not only as the Officer in charge of the Collections on the study of which they are based, but also in the interest of zoological science.