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Show 1886.] MADREPORARIAN CORAL. 129 there was no trace of any shell or other foreign body to be detected as was the case with two other species of the same genus as described by Prof. Moseley (1, page 154). From the pedicel radiate costae corresponding to the primary, secondary, and tertiary septa. The costse are formed by ridges along which are a series of blunt points. Between the basal costae the corallum is granulated, the granules running in lines and corresponding, not to the septa, but to the interstices between them. On the side-wall of the corallum, however, the ridges and points become much sharper, and there arise costae corresponding to the quaternary and quinary septa ; these are smooth and do not bear the points with which the primary, secondary, and tertiary costae are provided. The single specimen from which this species is described has unfortunately been broken and has re-mended itself, so that it is malformed, for there are only nine larger septa (i. e. primary and secondary) ; no doubt had the specimen been an uninjured one it would have possessed the typical Madreporarian number of twelve (i. e. six primary and six secondary). The coral will therefore be described on this assumption. There are five cycles of septa-six primary, six secondary, twelve tertiary, and forty-eight quinary, in all ninety-six. The secondary septa are distinguished from the primary by bearing large stout pallial elevations, each septum bearing two, the smaller one being the more central; the primary septa also bear pali, but they are not so large or distinct as those of the secondary septa. The tertiary septa are also slightly thickened at their inner ends. The ends of the primary, secondary, and tertiary septa are all fused with a very thick up-rising of calcareous matter, the columella, which bears five or six rounded projections resembling the true pali, but much lower, showing how the columella has been formed by the central ends of the septa and their pali. This knobby top of the columella forms a floor to the central part of the enteron of the polype, and it is much shallower than the surrounding chambers between the septa, where the floor is formed by the true base of the corallum. The quaternary septa do not quite reach the columella, but they are bent, inwards so as to touch the tertiaries ; those lying to the immediate left of the tertiary septum being shorter and joining the tertiary septum at a point nearer the circumference than those on the right, as is best seen in the figure (Plate XII. fig. 1). The quinary septa are much shorter than the others, only reaching halfway along the base of the theca and ending in two small upgrowths which seem to represent two rudimentary pali; no rudiments of pali could be seen on the quaternaries. All the septa are extremely exsert, the primary and secondary septa more especially so, so that in the specimen the tissuey did not cover their sharp edges; but this is probably due to the contraction caused by the spirit. It is only the outer halves of the primary and secondary septa PROC. ZOOL. Soc-1886, No. IX. 9 |
