The Atoll of Funafuti, Ellice group : its zoology, botany, ethnology and general structure based on collections made by Charles Hedley of the Australian Museum, Sydney, N.S.W.
Sub-Order Hydrocorallinæ. — Family Milleporidæ
Millepora squarrosa, Lam.
Millepora squarrosa, Lam., var. incrassata, Dana, U.S. Explor. Exped., Zoophytes, pl. liii., fig. 1; Synop. Rep. Zooph., 1859, p. 105.
A single example of this species is in the collection.
The specimen consists of a subtriangular plate 12·5 cm. in height, 18 cm. in width, from 1 to 1·5 cm. in thickness near the base, and from 1·5 to 2·3 cm. at the summit. The upper semi-circular margin is much thickened, lobate and roundly truncate; at one extremity there are two toe-like lobes 5 cm. high, 3·3 cm. broad, 1·3 cm. page 375thick at their origin and 2 cm. at their apex, their outer lateral margins are thick, their inner ones thin and acute. The rest of the upper margin consists of one broad lobe with three shallow indentations. The general surface is uneven, having a few low round or ridge-like elevations, and numerous shallow depressions in which the very regular cyclosystems are situated.
The gastropores are absent from the thick apical ridge, elsewhere they are very evenly distributed; they are on an average about 2 mm. apart and 0·25 in diameter. The dactylopores are generally confined to a limited area around the gastropores; they vary in number from four to six, their diameter is about 0·12 mm. and their distance from the central pore between 0·2 and 04 mm.
The surface is minutely porous and reticulately ridged; the ridges are pretty regular, about 0·05 mm. apart.
Millepora platyphylla, Ehrenberg.
Millepora platyphylla, (Ehrenberg) Dana, U.S. Explor. Exped., Zoophytes, p. 548, pl. lii., fig. 5.
A small fragment from the upper portion of a colony is in the collection.
The piece consists of three or four flat lamellæ, two of which have grown out vertically and at right angles to the main frond. The lamellæ are from 1 to 2 cm. in thickness, the apical margin is somewhat thin and rounded, the lateral margins are acute.
The surface is slightly tuberculous; the tubercles are low, rounded and longitudinally arranged.
Pores very unequally distributed, not distinctly arranged in systems. Gastropores irregularly scattered, 02 mm. in diameter. Dactylopores usually about 0·1 mm. in diameter, unevenly distributed over the whole colony. Surface reticulation with very minute ridges, usually under 0·05 mm. apart.
Millepora nodosa, Esper.
Millepora nodosa, Esper, Die Pflanzenthiere, pl. ix.; Moseley, Chall. Rep. Zool,, ii., p. 18, pl. xiii., fig. 3.
There are several fine examples referable to this species; of these three are well marked forms differing considerably in habit, but very similar in the cyclosystems and in the minute structure of the surface.
Form A.—The finest example possesses a large incrusting base inclosing a mass of dead material of the same species. From the upper surface there arises a series of irregular flattened lobes and page 376branches; the summits are usually obliquely truncated, and either acute or evenly rounded. The larger branches bear from two to three lobe-like branchlets similar to those figured by Moseley in the " Challenger " Report.
The specimen measures 17 cm. by 8 cm. at the base; the main branches are from 3 to 6 cm. wide at their origin, and from 1 ′2 to 2 cm. in their shorter diameter.
Form B.—The specimen consists of a compressed branched frond 19·5 cm. high, 7 cm. wide at the base, and 1·7 cm. in thickness. At a distance of 8 cm. from the base there arise two main branches; each gives off a few flat lobes at the sides and terminates in three or four subpalmate lobes.
Form C.—Consists of an antler-like reticulate frond, with widely divaricate and frequently coalescent branches; they are either alternate or opposite, and subdichotomous, especially near the summits. The terminal branchlets are a little compressed in the plane of branching; the rest, including the basal portions, vary from oval to subquadrate in transverse section, and measure from 1 to 2 cm. in diameter.
Another specimen is intermediate in habit between forms B and C.
The general surface in all the examples is characterised by numerous small elevations upon which the pore systems are situated; this is especially marked on the younger parts of the corallum, elsewhere they are not so conspicuous.
The gastropores are usually about 0·28 mm. in diameter, and from 1 to 2 mm. apart, they are somewhat crowded, but rather irregularly distributed. The dactylopores are about 0*18 mm. in diameter, they are very numerous and not distinctly arranged in cycles except on the younger parts of the colony.
The surface reticulation is rather coarse as compared with other species; the ridges are On an average fully 0·1 mm. apart.
Millepora Tortuosa, Dana.
Millepora tortuosa, Dana, U.S. Explor. Exped., Zoophytes, pl. lii., figs. 3-3a.; Synop. Rep. Zoophytes, p. 105.
This species is represented by a single specimen, closely resembling Dana's figure. The main branches are, however, a little broader, varying from 5 to 12 mm. in width. The whole surface of the branches is covered with very fine slight elevations upon which the pore systems are situated. The gastropores are very page 377evenly distributed; they are generally under 2 mm. apart and about 0·2 mm. in diameter. The dactylopores are about 01 mm. in diameter, and pretty regularly arranged in cycles.
The surface ridges are about 0·1 mm. apart.
* Moseley—"Challenger" Report—Zool., ii., pl. xiii., fig. 3.