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Show 756 MR. J. STANLEY GARDINER ON [June 6, 9. ORBICELLA HELIOPORA Lamarck. (Plate XLIX. fig. 4.) Astrea heliopora, Lamarck, Hist, des Anim. s. Vert. ii. p. 263 (1816). Heliastrcea heliopora, Milne-Edwards & Haime, Cor. ii. p. 459 (1857). Milne-Edwards and Haime have already given a full description of this species, with which two specimens in m y collection very closely agree. There is a considerable amount of variation in m y larger specimen, the thecae of neighbouring calices being in some parts closely apposed, and in others 2-3 m m . apart with a very distinct valley between. The septa show a condition approaching that found in 0. coronata, 0. curta, and 0. rotumana, the primaries being markedly broader at their upper edges than the secondaries. All the primaries and most of the secondaries meet the columella and are provided with paliform lobes. In the smaller specimen, a young colony, the crateriform character of the calices is more marked and the calices are rather deeper, being often 4-5 m m . Funafuti; leeward reef. 10. ORBICELLA SOLIDIOR Milne-Edwards & Haime. Astrcea solidior, Milne-Edwards & Haime, Ann. des S c Nat. ser. 3, xii. p. 102 (1850). Heliastrcea solidior, Milne-Edwards & Haime, Cor. ii. p. 460 (1857). Three specimens, which closely correspond to the descriptions. The calices in all the specimens have distinct low rims, separated by shallow valleys. The columella is always very dense and well marked, being formed by trabeculae from all the septa of tbe first two cycles and some also of the third cycle. While the costae are of equal size, the septa of the different cycles are quite distinct, those of lower cycles being more exsert, thicker, and broader than those of higher cycles. Paliform lobes are only found on the primaries and secondaries. Funafuti; lagoon reefs. 11. ORBICELLA FUNAFUTENSIS, n. sp. (Plate XLIX. fig. 5.) The corallum is a large incrusting mass covered underneath by a dense epitheca. The corallites are free at their edges-the thecaB being often 2-3 m m . distant-but there is no distinct valley between. The costae are nearly of equal size and thin ; they are joined on neighbouring corallites by exotheca and are never continuous. The calices are generally round, but sometimes more or less oval, never polygonal. The septa form three complete cycles, and commonly in one half of each system two septa of a fourth cycle are found. The primary septa are recognizable in all the calices, being slightly thicker and broader at their upper edges than the rest, and having low, broad, blunt paliform teeth before they join |