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Show 1899.] ASTRcElD CORALS FROM THE SOUTH PACIFIC. 741 Funafuti and Rotuma, but it cannot apparently withstand the force of heavy breakers. The specimens belong to five species, of which three were described by Milne-Edwards and Haime without figures. Carefully comparing all Milne-Edwards and Haime's descriptions of the species of the genus, and further comparing them with Ellis and Solander's, Esper's, and Dana's descriptions and figures, I have no doubt but that the specimens really belong to the species described by those authors. I have described one species as new under the name of G. edwardsi. This species is closely related to C. bottai, which has been probably correctly identified by Klunzinger with C. arabica var. leptochila Ehrenberg. From Klunzinger's description of this species, however, the characters of G. edwardsi would appear to be of good specific value. 1. COSLORIA DCEDALEA Ellis & Solander. (Plate XLVI. figs. 1,2.) Madrepora dcedalea, Ellis & Solander, Zooph. p. 163, pl. xlvi. (1786). Madrepora dcedalea, Esper, Forts. Pflanz. i. p. 63, pl. lvii. fig. 1 (1797). Cceloria dcedalea, Milne-Edwards & Haime, Cor. ii. p. 416 (1857). I have referred four specimens to this species, which vary very much among themselves, but yet present certain common features. The colony forms large hemispherical masses, which die in the centre while continuing to grow at the periphery. The calices in the centre of such a mass are generally circumscribed, while near the periphery they form series often 3-4 cm. long. The growing edge is generally thick, and the under surface is covered by a thick, concentrically-marked epitheca. The theca appears to be formed by thickening on the septal sides, and hence possesses a very ragged upper edge. The calicular walls are at first thin plates, formed by the fused thecae, but, if the growth of the colony is slow, may thicken enormously by a deposition within the calices of vesicular corallum. The septa belong to three cycles, of which the primaries and secondaries are nearly equal and fuse with the columella; the tertiaries are thin, narrow, and often wanting. There are 10-13 septa present in 1 cm. in the serial calices. The primaries and secondaries are continuous over the theca between the valleys, and are commonly about 1 m m . exsert. Generally the septa are thin, with ragged edges ; their outlines vary enormously, but in section, between series, the larger septa are seen to form broad arches over the theca, with almost vertical edges, abruptly broadening towards the fossae. The columella increases in size with the thickness of the theca, and is formed by the swollen septal edges and by trabeculae from the septa, the whole forming an almost imperforate plate in the base of the valleys. Rotuma; common in the boat-channel, where it forms large P R O C , Z O O L . Soc-1899, N o . XLVIII. 48 |
