| OCR Text |
Show 27<i MR. W. S. KENT ON NEW MADREPORES. [Apr. 4, This species differs from Acanthocyathus grayi (M.-Edw.), the only recorded existing form, in the straight instead of curved contour of its corallum, in its prominent costa. bearing spinous processes on others besides the two lateral primary ones, and in its more particularly exsert primary septa. Its costal peculiarities seem to demonstrate its being more closely allied to A. hastingsee (M.-Edw.), a species occurring as a fossil in the Miocene deposits of Malta. Figs. 1 b and Ic of Plate XXIII. illustrate various stages of development of A. spiniger; the extra spines present in fig. 1 appear to be characteristic of the adult condition. Though all the specimens examined are free, each exhibits traces of an early attachment. FLABELLUM MATRICIDUM, n. sp. (Plate XXIII. figs. 2, 2 a, b, ci) Corallum elongate, almost cylindrical, attached by its base. Calicular fossa circular, very deep. Theca exceedingly slender, invested by a complete epitheca. Septal cycles four in number, the last cycle incomplete. Primary and secondary septa scarcely exsert; lateral surfaces of septa granulate, their inner edge delicately flexuous above, thickened inferiorly, aud becoming lost in the trabecular elements of the rudimentary columella. Costae even, distinct throughout. Hab. Japan. B.M. The mode of increase in this species is exceedingly remarkable, resulting from internal gemmation at the expense of the parent calyx in the following manner:-The adult condition being arrived at, a bud makes its appearance immediately within the margin of the calyx, and, rapidly increasing in size, becomes confined by the opposite wall of the parent ; this, owing to its tenuity and the pressure exerted upon it, fractures and falls to pieces, the young bud still remaining attached to the portion from which it originated. Family OCULINID_E. AMPHIHELIA INFUNDIBULIFERA, nobis. (Plate XXIV. figs. 4, 4 a, bi) O. ramosissima, subfiabellata ; ramulis ultimis minimis flexuosis; stellis infundibuliformibus, interne striatis; margine crenulato. Oculina infundibulifera, Lamarck, Hist, des Anim. sans Verteb. p. 286, 1816. Allopora (Stylaster) infundibulifera, M.-Edw. Hist, des Corall. t. ii. p. 131, 1857. Specimens in the British Museum, collected at Formosa by Consul Swinhoe, are evidently identical with the species described as above by Lamarck ; but the entire absence of a columella and the unequal development of the septal cycles preclude its being referred to the group of the Stylasterace_e, as proposed by Milne-Edwards. These characters, when added to the alternate distal mode of increase of the calices, and the remarkable development of the basal |
