OCR Text |
Show 1897.] FROM THE S.W. PACIFIC OCEAN. 951 the same size, very deep, angular, and thin-walled, but generally between the verrucae and low down in the colony they are round, about *8 m m . in diameter. The ccenenchyma is well developed, and near the base of the colony generally separates the calices by about half their diameter ; the surface is covered by low spines, which may form striations between the calices. The stereoplasm is usually little developed. Commonly 12 septa and a small columella can be distinguished, but the primary are often very distinct spiny lamellae, one directive prolonged to meet a small, prominent columella, or both septa and columella inay be indistinct. The living colony is colourless, pink or green. Funafuti; outer reef. Botuma; outer reef and 2 fathoms. Lifu, Loyalty Islands. I have retained tbe name of P. grandis for this species to avoid a synonym, as I have no doubt that it is the same species as Dana described under this name. Tbe colonies grow in the fissures of the outer reef in great abundance, and, where their branches reach and project above low tide, they tend to be thickened, flattened above, and bare. There is a good series between P. elongata of Dana and P. grandis, and some smaller specimens resemble closely P. elegans of Dana, so that I have been compelled to unite these species; in the description of P. egdouxl there do not seem to be any characters which would serve to separate it either. The same specimen is often in places very diverse in its growth and in the arrangement of its septa and columella, so that I do not think the differentiation of varieties advisable. I have referred to the same species a small incrusting clump 7 cms. broad by 3 cms. high, found in the breakers at Botuma; its verrucae and cells are similar to the type, and it seems to be tbe much stunted commencement of a colony. The specimen nearest to P. elongata (Plate LVII. fig. 3) is a branch 21 cms. long by 3-4 cms. broad ; its septa and columella are very distinct. It was growing out from under tbe overhanging edge of a fissure in the reef, and has its side towards the rock almost bare of verrucae, which, however, cover the opposite side verv evenly. There are two small branches coming off, which subdivide into numerous smaller branchlets, giving them quite a bushy appearance. Their verrucae are larger than in the main branch ; their calices, however, are of the same size and have a distinct star and columella, but the ccenenchyma between them is generally more developed. 20. POCILLOPORA GLOMERATA, n. sp. (Plate LVI. fig. 1.) Corallum a low, glomerate, slightly hemispherical, semi-incrusting mass with a few lobe-like, somewhat compressed branches up to 2 cms. in length, 10-15 mms. thick. The apices and sides of the branches are generally bare, but some are sparingly covered by low round, much appressed verrucae. Calices of the verrucae 1-1*2 mms. in diameter, round and rather deep, of the apices of ^he branches about *8 mm., usually angular and thin-walled, and |