Art. L.—Sponges collected at the Kermadec Islands by Mr. W. R. B. Oliver.

By Professor H. B. Kirk, M.A.

Genus Tethya Lamarck.

More or less spherical Tethyidae, without highly specialized pore-bearing grooves, and without a sand-layer in the choanosome.

Tethya lyncurium Lin. var. australis var. nov. Fig. 1.

Sponge about 2 cm. in diameter and 1·5 cm. in height. Surface marked by rounded elevations and depressions, the elevations echinated by the spicules of the brush. No appearance of tesselation. Colour of formalin-preserved specimen pale yellow.

Fig. 1.—Tethya lyncurium var. australis. 1a, 1b. Styli. 2. Strongyle. 3. Oxeote. 4. Spheraster. 5. Chiaster.

The general arrangement of the skeleton is that of the typical T.' lyncurium. Megascleres are for the most part styli (fig. 1, 1a, 1b) with the base rounded, the apex usually blunt but sometimes sharp, and the widest part of the spicule about a third of the distance from the base. The styli vary in size; an average size is 1·3 mm. by 0·02 mm. There are

a smaller number of strongyloxea, 1·05 mm. by 0·015 mm., and a few undoubted oxea, 0·9 mm. by 0·015 mm. Spicules of all three kinds occur also in the choanosome, between the rays. The microscleres are very small chiasters, and larger and more massive spherasters. The chiasters are most abundant just at the surface of the sponge, where they form a close layer, as in the type (see Bowerbank, “British Spongiadae” vol. 2, p. 93). They are also abundant in the inner portion of the ectosome, and are freely scattered throughout ectosome and choanosome. The spherasters are unevenly scattered through the ectosome, and are rare in the choanosome. The chiasters have a very small centrum, and about 12 slender straight rays always distinctly tylote. This tylote termination of the rays is like that of T. japonica, figured by Sollas (IX, pl. xliv), and that of T. lyncurium var. a, described by Dendy (IV, p. 113). The chiaster is noticeably different from that of the type as figured by Schmidt (VIII, pl. iv), Carter (XI, pl. ii), and others. Length of ray, 0·01 mm. The spheraster has a massive body and from 12 to 18 stout pointed rays, which are never spined. The length of the ray is 0·02 mm., and the total diameter of the spicule 0·06 mm.

This sponge is identical with one found on the New Zealand coasts, but not hitherto described. It is perhaps identical with Lendenfeld's T. multistella (V, p. 46), in which, however, no strongyloxea nor oxea are reported. It is also very near Dendy's T. lyncurium var. a (IV, p. 113). I note these points of difference :—

I propose to establish this variety with some reluctance, and only do so to avoid any possible confusion in notions of distribution.

Five specimens were received, preserved in formalin. “Meyer Island, near Sunday Island, in rock-pools; 24/4/08.”

Genus Reniera Nardo.

Skeleton forming a close reticulation of usually single megascleres, each forming one side of a mesh. Spicules short, usually oxeote. In most cases the ends of the spicules are bound to the adjacent spicules by a little spongin.

Reniera reversa n. sp. Fig. 2.

Sponge flattened and encrusting. Length, 4·5 cm. Thickness, 0·7 cm. There are a few scattered oscula flush with the surface of the sponge, and about 4 mm. in diameter.

The skeleton consists mainly of blunt oxea, which are slightly curved. These are bound together by scarcely discernible spongin into meshes which may be 3-, 4-, or 5-sided. From the upper surface of the sponge there project slightly curved styli, the blunt end directed outwards. These are imbedded for about half their length. They form various angles with the surface.

Size of spicules: Oxea, 0·1 mm. by 0·005 mm.; styli, 0·84 mm. by 0·014 mm.

Two specimens were received, dry and somewhat broken. The label reads. “Taken in rock-pools, Meyer Island (near Sunday Island); 29/2/08.”

Fig. 2.—Reniera reversa 1. Section of skeleton at right angles to surface. 2, 3. Styli. 4. Oxea.
Fig. 3.—Chalina fistulosa. 1. Portion of dermal skeleton. 2. Section of skeleton at right angles to surface. 3. Oxea.

Genus Chalina Grant.

Chalininae whose skeletal reticulation is typically rectangular. Fibres usually slender, with much spongin, and few, but usually well-developed, spicules.

Chalina fistulosa n. sp. Fig. 3.

Sponge massive, sessile; with well-developed oscula, oval or rounded, which terminate short fistular processes on the upper surface of the sponge. Fistulae from 5 mm. to 12 mm. in height; oscula from 5 mm. to 8 mm. in diameter. Surface smooth. Colour of dry specimen dirty-yellow. Texture harsh.

Internal skeleton showing approximately rectangular meshes. Longitudinal fibres usually a little stronger than the transverse ones, and loosely cored with a strand of spicules often arranged with some irregularity. In the transverse fibres the spicules are few, never forming a connected strand and never polyserial.

Dermal skeleton shows fibres that are about the same diameter as the primary fibres of the internal skeleton, but dark in colour. They form a

polygonal network, the meshes of which are broken up by finer, irregular fibres of light colour. Spicules are never polyserial in the dermal skeleton, and are more numerous in the secondary fibres. Many lie outside the fibres.

Spicules are all oxea, straight or slightly curved, running somewhat suddenly to a fairly sharp point. Size, 0·05 mm. by 0·004 mm.

This sponge appears to be close to Dendy's C. clathrata (IV, p. 151) and to Topsent's C. similis (X, p. 481).

A single dry specimen received. “Cast up on Denham Bay beach, Sunday Island; 27/7/08.”

Genus Toxochalina Ridley.

Ridley (VII, p. 402) founded the genus Toxochalina for “Chalinidae with well-developed horny fibre arranged rectangularly. Spicules, a skeleton acerate and a tricurvate acerate (“Bogen”) flesh spicule.”

One of the Kermadec Island sponges is a Chalina in every respect of structure, except that it has minute flesh spicules in the form of oxea. In view of the fact that many of the Chalininae have been described from beach-worn specimens, and some of them may yet be found to possess flesh spicules, it seems unwise to establish—at present, at all events—a new genus differing from Toxochalina only in the form of its microscleres. I therefore suggest a slight emendation of the generic character to admit sponges differing from Chalina in the presence of simple linear microscleres.

Toxochalina oliveri n. sp. Fig. 4, and Plate XXVII, fig. 2.

Sponge attached by the greater part of the lower surface. Oscula prominent, on the summit of rounded elevations on the upper surface, or on the crest of level ridges formed by the concrescence of such elevations. Colour yellowish-buff. Texture firm. Length of specimen, 9·5 cm.; width, 6 cm.; height, 1·5 cm.

Structure of skeleton: Primary fibres running in parallel or in radiating lines to the surface, connected by the secondary fibres, which form with them and with each other rectangular mesches. The primary fibres contain an uneven strand of oxea loosely and irregularly arranged, most numberous at the nodes. The strand thins out in places to the point of disappearance, but usually it consists of about six series of spicules. Secondary fibres thinner than the primary, containing few spicules, and these not polyserial and not in contact end to end. The general appearance of a section of the skeleton is very like that of Siphonochalina procumbens as figured by Dendy (III, pl. 58, fig. 4). In the dermal skeleton the meshes are subdivided by finer fibres (fig. 4, 2).

Fig. 4.—Toxochalina oliveri. 1. Section of skeleton at right angles to surface. 2. Portion of dermal skeleton. 3. Oxea. 4. Microscleres.

Spicules: The spicules of the skeleton are slightly curved oxea with bluntish ends. Size, 0·24 mm. by 0·008 mm. The microscleres are minute strongyla, smooth and straight or slightly curved.

The sponge is quite unlike Toxochalina foliodes(Desmacidon foliodes Bowerbank), reported by Lendenfeld (VI, p. 797) from Thursday Island. That sponge is not in Mr. Oliver's collection.

A single dry specimen received. “Cast up in Coral Bay, Sunday Island; 2/5/08.”

Genus Clathria Schmidt.

“Ectyoninae of various habit, frequently clathrous. Skeleton a reticulation of fibre, usually with much spongin, containing smooth styli and echinated by spined styli.”—Dendy (IV, p. 170).

Fig. 5.—Clathria intermedia.
1. Portion of skeleton. 1a. Portion of skeleton at right angles to surface. 2 a, b, c. Echinating smooth styli. 2 d, e, f. Smooth styli, sometimes echinating, more often in fibre or in sponge-flesh. 3 a, b, c, d, e. Smooth slender styli of fibre and sponge-flesh. 4. Echinating spined styli. 5. A diact spicule in boiled-out preparation. 6. Toxa. 7, 8. Isochelae. 9. Simple sigma.

A Clathrioid sponge in Mr. Oliver's collection has both smooth and spined echinating styli. I think it best to interpret the generic character as to echination to mean that there must be spined echinating styli and that there may be smooth echinating styli as well, rather than to establish a new genus for this sponge.

Clathria intermedia n. sp. Fig. 5.

Sponge massive, encrusting, harsh to the touch. On the upper surface are numerous low, conical elevations, each terminating in a circular osculum, which is about 3 mm. in diameter.

The single specimen is 5 cm. long, 1·5 cm. high. Colour brownish-grey.

Skeleton showing primary and secondary fibres. The former generally radiate from the walls of the gastral cavity to the surface; the latter connect the primary fibres, giving approximately right-angled meshes. Colour in balsam light amber. The primary fibres are cored by a strand of smooth styli, the strand being from 1 to 4 spicules thick. The apex of the spicules is nearly always directed towards the surface of the sponge, where one or two of these smooth styli may project from the end of the primary fibres. Secondary fibres seldom contain spicules. Both primary and secondary fibres are echinated sparsely by smooth and by spined styli in about equal numbers. Only the base of the echinating spicule is imbedded in the spongin, and the spicules project at almost right angles to the fibre. There is no special dermal skeleton. The sponge-flesh contains abundant smooth styli showing no definite arrangement.

Spicules: Megascleres all styli. (1.) The most characteristic are fairly stout spicules with well-rounded base, the broadest part of the spicule being about one-third of the length from the base. These spicules usually run abruptly to a sharp point. Size, 0·1 mm. by 0·009 mm. The smooth echinating spicules are all of this kind, as are most of these that core the fibres or that lie loose in the sponge-flesh. In the latter position the styles may be blunt, and there are long and slender styli. The most slender have a thickness of about 0·001 mm., and these may be variously curved. (2.) Spined styles occurring as echinating spicules only; somewhat tylote, spines irregularly scattered, directed straight outwards. The spicule tapers to a fairly sharp point. The apical portion of the spicule—about one-sixth of the whole length—is the only part that is always free from spines. Microscleres —(1) Isochelae, palmate. As the spicule lies on its side it presents a distinct indentation on the convex side; this represents the shank of the spicule, along which the palmate expansion does not extend. (2.) Simple sigmata, somewhat larger than the isochelae. These are few in number. (3.) Toxa, slender, sharp-pointed; usually with a well-marked primary curve, and feeble secondary curves.

A single dry specimen. “Cast up on Denham Bay beach, Sunday Island; 27/7/08.”

Genus Clathriodendron Lendenfeld (V, p. 215).

“Desmacidionidae with exceedingly large tylostylote megasclera. The spongin fibres of the supporting skeleton contain only few spicules. Echinating spicules spined styli.”