OCR Text |
Show 1899.] ASTRcElD CORALS FROM THE SOUTH PACIFIC. 763 growth of Millepora-generally not more than 1 mm. thick-has taken place, which over the dead calices very closely follows their septa. On the surface, too, a young colony of the same species of Galaxea is situated ; it has 16 corallites, the largest being 3 mm. in diameter. In the young corallites at the edges of the colonies all stages, from a cycle of six septa to the full three cycles, can be found. In the older calices the typical number of septa for three cycles, i. e. 24, is by no means constant, as many as 30 often being found, and it would appear that these are true variations in the number of septa and are not due to the presence of a few septa of a fourth cycle. In all cases thick and thin alternate, the latter situated always more externally on the theca. 2. GALAXEA FASCICULARIS Linnaeus. Madrepora fascicularis, Linnaeus, Syst. Nat. edit. xii. p. 1278 (1763). Madrepora fascicularis, Ellis & Solander, Zooph. p. 151, pl.xxx. (1786). Galaxea fascicularis, Milne-Edwards & Haime, Cor. u. p. 227 (1857). After some hesitation I have referred two small specimens to this species. They agree in most respects with the above descriptions, but the calices are rather smaller, the largest being less than 1 cm. in greatest diameter and the majority only about 7 m m . The corallites and peritheca are comparatively light, and some of the former project for 2*3 cm. above tbe latter, the general height being little more than half this. The lower part of the peritheca has been destroyed, generally to within 6 m m . of its free surface, bv boring organisms. The lower parts of the corallites remain, being formed of dense corallum, and tbe whole appears to have been°growing very rapidly, perhaps owing to tbe boring organisms acting as a stimulus. Wakaya, Fiji; reef. I also obtained a single corallite of a colony of the same species from the chain ot a buoy in Levuka Harbour, Fiji, which had been cleaned 22 months before. The corallite measures 2-3 cm. m height and 7*5 m m . by 5 m m . in diameter, so that the colony of which it formed a part must have been of considerable size. EXPLANATION OF T H E PLATES. PLATE XLVI. Cozloria dcedalea, Ellis & Solander. Specimen b, X 1; p. 741. d> x h sinensis, Milne-Edwards & Haime, X 1; p. 742. astrceiformis, Milne-Edwards & Haime, X 1; p. 743. "„ esperi, Milne-Edwards & Haime, p. 743. „ edwardsi, n. sp., X 1; p. 744. Pig. 2. 3. 4. 5. 6. |