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Show 1900.] MARINE FAUNA OF CHRISTMAS ISLAND. 121 long), from what I take to have been a prostrate, or other one-growth-form. The branchlets are all turned up one side and grow out at right angles, and the scoop-shaped radial calicles project on the same side also at right angles and are chiefly obsolete on the opposite side. The branches show no trace of fusing together. In other respects, however, it comes nearest to Madrepora clathrata. The calicles, both radial and axial, seem to agree in shape and size, and the characters of the ccenenchyma seem to be the same as those described for this species. The specimens of this and the next species were broken from dense clumps growing on the reef-flat in water about one foot deep at low tide, when the tops of the clumps are exposed for some time. MADREPORA VALIDA. Madrepora valida Dana, Zoophytes, p. 461, pi. 35. fig. 1. There is a complete specimen consisting of a crowd of processes all reaching to about the same height (4 cm.), and rising from a common incrusting base, which seems to come near Dana's type. The tips of most of the processes in the single specimen had been injured, and the coral had attempted to heal the injuries. The axial calicles and a few of the nearer radial calicles are swrollen into coenenchymal knobs, without or with greatly reduced or distorted calicle apertures. Where not injured, the calicles have much the aspect described and figured by Dana, and the section of the processes shows the density of the coral, also mentioned by Dana. MADREPORA (?) ASPERA Dana. 3Iadrepora aspera Dana, Zoophytes, p. 46S, pi. 38. tig. 1. A specimen 8 cm. high, in which tbe tapering brauches more or less suddenly proliferate into a number of stunted outgrowths. The septa in the radial calicles show it to belong to the subgenus Eumadrepora Brook. The size of its axial corallite, the variously prominent and labellate radial calicles interspersed with minute obsolete calicles, seem to ally it with M. aspera. It differs chiefly in the greater crow-ding of the radial calicles, which were comparatively sparse in the type specimen. This species forms dense clumps growing on the reef-flat, and partly exposed at low-water. MADREPORA DELICATULA Brook. Madrepora delicatula Brook, Ann. & Mag. Nat. Hist. viii. 1891, p. 461. There are two small detached clusters of twigs which agree with the branchlets of Brook's type of 31. delicatula. The measurements and shapes of the calicles both axial and radial agree, as also do the markings on the surface as described. There is no evidence that the growth-form resembled that of |