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Show 1899.J ASTRcEID CORALS FROM THE SOUTH PACIFIC. 745 growing on the lagoon-shoals at Funafuti; I did not, however, find it ever on the reef itself in that locality. In Fiji it is very common, growing at Wakaya both in the lagoon and on the leeward reefs. The monticules of the Funafuti specimens are about 2*5 m m . distant from one another and 2 m m . high. On a Wakayan specimen from the lagoon they are 3-3*5 m m . distant and 2*5- 3 m m . high, and on one from the reef 3-4*5 m m . distant and 3-4 m m . high. The differences between the latter specimen and the Funafuti specimens are so striking that at first sight they would appear to belong to distinct species. The variations are probably, however, due to absence of sand and mud, together with a more abundant food-supply on the reef at Wakaya. The lagoon-shoals of Funafuti are but sparingly covered with corals, whereas the whole reef to leeward of Wakaya is in many places covered wdth very luxuriantly-growing Madreporaria, Millepora, Heliopora, and Tubipora to within about 15 yards of the breakers. The species forms large hemispherical masses, which commonly, as in Porites, die in the centre and are hollowed out, continuing to grow at the periphery. The monticules of the upper surface of an overhanging mass are somewhat pointed, while those of the lower surface are often flattened and very massive. Funafuti ; Wakaya, Fiji; Rotuma (spirit-specimens only). 2. HYDNOPHORA LOBATA Lamarck. (Plate XL VIII. fig. 2.) Monticularia lobata, Lamarck, Hist, des Anim. s. Vert. ii. p. 250 (1816). Hydnophora lobata, Milne-Edwards & Haime, Cor. ii. p. 421 (1860). One small specimen, which corresponds fairly well with the descriptions. It is a bifid lobe apparently torn off from a large massive colony. The monticules vary up to 7 m m . in length, and are from 2*5 to 5 m m . distant from one another and 3-5 m m . high. O n the opposite sides of the valleys thick and broad septa alternate with thin and narrow. The broad septa apparently bifurcate and meet one another, fusing in the centre of the valleys; the large septa of one monticule lie then opposite to the small septa of the neighbouring monticules. The sides of the septa are granular and their edges are entire, save that the large septa have conspicuous vertical teeth where they bifurcate. The interseptal loculi vary up to 8 m m . in depth, and are closed below by horizontal partitions of endotheca. Funafuti; 20 fathoms outside the reef. 3. HYDNOPHORA EXESA Pallas. (Plate XLVHI. fig. 3.) Madrepora exesa, Pallas, Elench. Zooph. p. 290 (1766). Hydnophora demidovii, Fischer, Mus. Demidoff, iii. p. 295, pl. iv. (1818). Monticularia polygonata, Lamarck, Hist, des Anim. s. Vert, ii, p. 250 (1816). |