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Show 187L] MR. W. S. KENT ON NEW MADREPORES. 281 pit-like interseptal chambers, as in the preceding species. Columella deeply immersed, cylindrical, echinate, its apex pointed. Surface of the main stem and the origins of the branches delicate rose-madder, the ultimate ramifications almost white. Length and breadth of entire corallum of the single specimen examined three and a half inches; diameter of the main stem half an inch, of the calices half a line. Ampullae rudimentary, in the form of minute vesiculae, distributed among the calices throughout the branches, though in greatest profusion towards their distal extremities. Hab. Unrecorded. Sir E. Belcher's Collection. B.M. The form referred to this genus as A. oculata by Dr. P. M. Duncan, in his description of the ' Porcupine' Expedition (Madreporaria, Proc. Roy. Soc. p. 295, 1870), is a true Stylaster, closely allied to S. gemmascens (M.-Edw.), Madrepora gemmascens, Esper (Pflanzenthiere, t. i. pl. 55, 1797), inhabiting the Indian seas. The gemmation in this species, though at first sight apparently irregular, is, on close examination, found to exhibit the alternate distal terminal gemmation and more or less attendant latero-linear arrangement of the calices on the main branches characteristic of Stylaster. Some time back Dr. Duncan kindly favoured me with a small specimen of this interesting coral, and since then he has permitted me to examine the whole series collected; but it being the property of the above expedition, I leave it to bim to furnish the name and specific diagnosis. Comparison with the figures of A. oculata in the ** Annales des Sciences Naturelles,' torn. xiii. pl. 4. fig. 4, 1850, shows that this species possesses altogether different characters. DISTICHOPORA ROSEA, n. sp. Corallum arborescent, branches nearly cylindrical. Calices occupying deep and occasionally irregularly interrupted lateral furrows ; margins of the furrows very prominent. Columella attenuate, stylate, echinate, very deeply immersed, made visible by fracture of the corallum. Height of corallum one or two inches ; diameter of the calicinal furrows ^ inch, of the branches | inch. Colour of the ccenenchyma bright rose-pink. Hab. East coast of Australia. B.M. As already shown by Count de Pourtales, the structure of the calices in Distichopora is identical with what obtains in Stylaster and Allopora, with the exception that the calices are confluent. In this respect Distichopora bears much the same relation to the two genera just mentioned as Lithophyllia and Dasyphyllia do to Mussa and Symphyllia among the Astreidae. In Distichopora isolated calices are occasionally met with'; and it is then that their similarity to those of other Stylasteraceae become most apparent. I must differ with Count de Pourtales in considering this genus to be more closely allied, individually, to Stylaster than to Allopora, the latero-linear disposition of the calices indicating their development from primary alternate distal rather than from an irregularly scattered gemmation. |
