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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.

Family Homorrhaphidæ

Family Homorrhaphidæ.

Reniera australis, Lendenfeld.

Reniera australis, Lendenfeld, Aust. Mus. Cat. xiii., Sponges, 1888, p. 78.

There are several examples of this species exhibiting considerable variation; one resembles a piece of pumice-stone with numerous crateriform oscula; others have a comparatively smooth surface, with dome-shaped oscula bearing processes.

page 325

On comparing the specimens with the type I find it presents exactly the same external characters.

The colour of the specimens from Funafuti varies from light to dark coffee brown, that of the type from Port Jackson is now (in spirit) burnt umber colour; in the description it is stated to be gray. The specimen is attached to a piece of wood, which may have stained it this colour.

The spicules exhibit a little variation in size, but the average is about the same as in the type, i.e., 0·12 by 0·004 mm.

Low water-mark on reefs in the lagoon.

Reniera sp.

This form appears to be identical with No. 42 Reniera sp. described by Ridley.*

There are numerous specimens in the collection, but owing to the fragile nature of the sponge all are more or less broken. The sponge consists of thin lamellæ, which form folds or tubes, with fairly large oscula at the summits; the tubes are from 5 to 10 mm. in diameter, and from 5 to 30 mm. in height, the walls are from 1 to 2 mm. in thickness, the oscula are 5 mm. in diameter. Texture very fragile when dry, in spirit slightly elastic, but easily broken if handled. Surface rather smooth in appearance to the unaided eye; when seen with a moderate magnifying power it is minutely reticulate with numerous round pores. Colour, when alive rose pink, in spirits pinkish gray.

Megasclera—Small curved oxea suddenly tapering to acute points, varying slightly in length and thickness, usually about 0·12 by 0·006 mm.

Possibly this form may be a variety of Reniera rosea, Bower-bank. According to Topsent, Reniera cinera, Grant, is identical with R. rosea, Bowerbank. Grant's species is recorded from the Philippines.

Mangrove swamp (ante p. 324).

Halichondria solida, var. Rugosa, Ridley & Dendy.

Halichondria solida, var. rugosa, Ridley & Dendy, Chall. Rep. Zool., xx., p. 4.

A single example agreeing with the description in colour, surface, and texture. The spicules, however, are slightly less in size; the larger, stouter forms are about 0·85 by 0·025 mm. They vary greatly in length and thickness; they are usually slightly curved and taper rather suddenly a few diameters from the ends, which are more or less rounded.

Reefs in the lagoon among the Sarcophyta.

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Spinosella glomerata, sp. nov. (Plate xviii., fig. 1).

Sponge, large cake-shaped, attached by a broad base. From the upper irregularly convex surface arise numerous short narrow tubes. The largest example is somewhat water worn, and measures 300 mm. in its long and 250 mm. in its short diameter, and about 70 mm. in height. The tubes vary greatly in size. The larger are 30 mm. in height, 10 mm. in external diameter, without the spinose processes, the internal diameter averages about 5 mm., the largest are about 8 mm. the smallest about 2 mm.

Colour of the dried sponge is light brownish gray.

The tubes are rarely free, being more or less united laterally throughout their length. The surface is beset with numerous prominent aculeations, they vary from 3 to 6 mm. in length, and are usually about 3 mm. apart; the summits of the tubes are fringed with from five to twelve of these processes. The dermal surface consists of a close reticulation of fine fibres, with numerous circular pores 0·2 to 0·5 mm. in diameter. The oscula are 1 to 1·5 mm. in diameter, and are fairly abundant on the inner surface of the tubes.

The main skeleton is composed of well developed horny fibre, with a polygonal or subrectangular mesh. The main fibres are from 0·8 to ·1 mm., the secondaries 0·5 mm. in diameter, the former are sparsely cored with slightly curved oxeote spicules, the latter by a series of three or four, in the slender connecting fibres the spicules are unior biserially arranged.

Megasclera—Slightly curved oxea with rather blunt points.

Size—About 0·07 by 0·002 mm.

Reefs in the lagoon at low water, plentiful.