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Show 250 MR. W. S. KENT ON NEW MADREPORES. [Api". 4, pointed. Colour of the trunk and main branches dull rose, lessening still more in intensity towards the branchlets, the ultimate ramifications of which are nearly white. No ampullae detected on the single specimen observed. Hab. Unrecorded. B.M. The unique specimen above described measures nearly a foot in height and nine inches in breadth, while the diameter of the most massive portion of the stem exceeds two inches, dimensions greatly surpassing those of any hitherto recorded representative of the Stylasteraceae. Both this and the species next introduced appear to be closely allied to Allopora miniata (Pourtales); but in this last form the calices are larger, are distributed on one surface only of the branches, and become entirely obsolete on the main stem. ALLOPORA EXPLANATA, n. sp. (Plate XXV. figs. 2, 2a, b, ci) Corallum branching, flabellate; the main stem and branches-massive, slightly flattened; the branchlets attenuate. Surface of the ccenenchyma shagreened as in the preceding species. Calices prominent, distributed with moderate density throughout the corallum ; half a line in diameter. Septal system very irregular, the septa being sometimes entirely wanting, or varying in number from one or two to as many as six or seven; when present frequently meeting within the margin of the calice, and enclosing a vertical fringe of points, as in Allopora nobilis. Columella deeply immersed, cylindrical, echinate, its apex pointed. Height and breadth of corallum five or six inches; diameter of the main trunk three-quarters of an inch. Colour of the surface of the selerenchyma closely resembling that of the species last described, but of a still brighter hue ; the distal extremities of the branchlets alone are yellowish white. Ampullae present or absent. Hub. Unrecorded. B.M. As a species this form differs from A. nobilis in the flabellate mode of growth of its corallum, in the more rudimentary development of the septal system, and in the more widely scattered calices. Of the two examples in the British-Museum collection, the one has large, smooth, vesicular ampullae, nearly a line in diameter, distributed amongst the calices of the branchlets and younger branches, while in the other a few slight and very minute prominences are the only visible traces of these excrescent structures, illustrating what little dependence is to be attached to them even for the purpose of specific comparison. ALLOPORA SUBVIOLACEA, n. sp. (Plate XXV. figs. I, I ai) Corallum branching, flabellate; the main stem and branches massive, compressed. Surface of the ccenenchyma less delicately shagreened than in A. nobilis and explanata. Calices slightly prominent, scattered throughout the surface of the corallum. Septa varying in number from three or four to as many as eleven (two cycles almost complete); never coalescing laterally, and forming |