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Show 750 MR. J. STANLEY GARDINER ON [June 6, represented in Klunzinger's figure. The large, distinct, primary septa are extremely characteristic. Funafuti; dredged in the South Ship's Passage from 5 fathoms. 7. ASTRcEA ROTUMANA, n. sp. (Plate XLVH. fig. 3.) The corallum forms large incrusting masses, covered underneath by a thin epitheca. The colony does not seem to increase much by fission and budding at the edge, which is very thick and costulated down to the epitheca. The calices vary from 6 to 11 m m . in diameter by 4-6 m m . in depth to the top of the columella. The septa are usually rather thin, except in their exsert portions, and the interseptal loculi are wide and deep. In the largest calices two orders of septa are complete and there are commonly 8 or 10 septa of the third order. The primary septa are about 2*5 m m . exsert, and about 2 m m. broad at the level of the thecal rim. Lower down they broaden out, the edges still low*er running almost horizontally into the columella, but giving off first each a blunt, vertical paliform tooth. In the smallest calices the primary septa alone join the columella, but in the larger calices often 3 or 4 of the secondary septa fuse with it as well. The latter may somewhat simulate the primaries, but the secondaries never attain the same exsertness nor are their paliform lobes well-marked. The tertiary septa are about 1 m m. exsert, and are very thin and narrow, being seldom more than 1*5 m m . broad. The walls vary from 1*5 to 3 m m . in thickness, and the rims of the calices are about 1 m m . high. The septa are not continuous between the calices, so that the sulci are very conspicuous and deep. The columella is formed by fine, loosely joined trabeculae from the septal edges, and in the larger calices, in which it is often 1-1*5 m m . broad, has a finely papillate surface. In the smaller calices the columella is often scarcely visible. The interseptal loculi are open for about 1 cm., below which they are closed by nearly horizontal endothecal dissepiments, about 1 m m . distant from one another. The thecae of neighbouring corallites are joined also by similar exothecal dissepiments. (PL X L V H . fig. 3.) Rotuma ; a single specimen, 13 cm. long by 1 cm. broad, part of an incrusting mass. 8. ASTRCEA AFFINIS, Milne-Edwards & Haime. Favia affinis, Milne-Edwards & Haime, Cor. ii. p. 429 (1857). I have referred a single specimeu with 19 calices to the above species, as it differs from A. denticulata and agrees with the above species in the characters given by Milne-Edwards and Haime. The dividing walls of the specimen are as thick as in my specimens of A. denticulata, but the thickness varies enormously in all species of Astrcea. M y specimen is too small for any definite statement, but the two species will, I think, be found to be identical. Wakaya, Fiji; outer reef. |