280 MR. W. S. KENT ON NEW MADREPORES. [Apr. 4, 



pointed. Colour of the trunk and main branches dull rose, lessening 

 still more in intensity towards the branchlets, the ultimate rami- 

 fications 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, 2 a, 6, c.) 



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 fre- 

 quently 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 sclerenchyma 

 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. 



Hab. 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 deve- 

 lopment 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 pro- 

 minences 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 a.) 



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 



