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Show 760 MR. J. STANLEY GARDINER ON [June 6, 3. PRIONASTRCEA PURPUREA Dana. Astrcea purpurea, Dana, Zooph. p. 239, pl. xii. fig. 10 (1848). Prionastrcea purpurea, Milne-Edwards & Haime, Cor. ii. p. 524 (1857). Dana states that this species differs from P. pentagona (Ehrenberg) only by tbe absence of a corona of teeth round the columella and the presence of a sulcus on tbe tops of the walls. Some of tbe calices of one of m y two specimens show a corona of broad teeth round the columella and the sulcus is not always present. I have, however, retained Dana's name, as Ehrenberg's description is useless without reference to the original specimens, which are unknown. The polyps and corallum agree absolutely with Dana's description and figures, except fig. 10/> of the septa. There are generally present 40-50 septa, of which about half are much thicker than the rest and fuse with the columella. The edges of these latter septa end usually in 6-9 fine rectangular teeth, often 1 m m . or more in length, and have rather a ragged appearance. The large septa are continuous between the calices with thin walls, but the sulcus is always marked by a deep notch immediately over the centre of the wall. The columella is always very well developed, usually oval in shape, about 3 mm. by 2 m m . It is generally situated about 2 m m . below the edges of the septa, and in surface view appears to be almost a solid mass, but is really composed of extremely fine aud closely anastomosing trabeculae. Rotuma ; reef with the preceding species. Two specimens. P. gibbosa of Klunzinger appears to come very close in its characters to this species and is almost certainly identical with it. One of my dried specimens is rather gibbous, but this is not a specific character. 4. PRIONASTRJEA HIRSUTA Milne-Edwards tfc Haime. Acanthastrcea hirsuta, Milne-Edwards & Haime, Ann. des Sc. Nat. ser. 3, xii. p. 145 (1850), and Cor. ii. p. 502, pl. D 5. fi-r 4 (1857). Acanthastrcea hirsuta, Klunzinger, Die Korall. des R. Meeres, iii. pl. v. figs. 1-2 (1879). I have referred a small colony with 19 calices to this species, with which it agrees absolutely in all the characters given bv Milne-Edwards and Haime. Budding takes place within the calices, and also very markedly over the costae at the edge of the colony. Funafuti. 5. PRIONASTRCEA ECHINATA Dana. (Plate XLVH. fig. 6.) Astrcea echinata, Dana. Zooph. p. 229, pl. xii. fig. 1 (1848). I have referred a single specimen (about which 1 have no notes as to colour) to this species, with which it agrees absolutely in all the described and figured characters. There are about 30 septa, |