PART I.. Genus Spongilla.

Genus SPONGILLA.

Subgenus EUSPONGILLA (p. 69).

1 a. Spongilla lacustris, subsp. reticulata (p. 71).

Specimens were taken in the lake Malwa Tal (alt. 3600 feet) in Kumaon, while others have recently been obtained from the Kalichedu irrigation-tank in the Pagnor talug of the Nellore district, Madras (G. H. Tipper).

4. Spongilla cinerea (p. 79).

Specimens were taken in Naukuchia Tal (alt. 4200 feet) in Kumaon. They have a pale yellow colour when dry. This sponge has not hitherto been found outside the Bombay Presidency.

Subgenus EUNAPIUS (p. 86).

8. Spongilla carteri (p. 87).

Specimens were taken in Bhim Tal (alt. 4450 feet) and Sat Tal (alt. 4500 feet). Some of them approach the variety cava in structure.

Subgenus STRATOSPONGILLA (p. 100).

12. Spongilla bombayensis (p. 102).

Add a new variety:--

13 a. Var. pneumatica, nov.

(i.) The sponge forms a flat layer of a pale brownish colour as a rule with short and very delicate vertical branches. In one specimen it takes the form of an elegant cup attached, only at the base, to a slender twig.

(ii.) The gemmules are covered, outside the spicules, by a thick pneumatic coat of irregular formation and with comparatively large air-spaces.

(iii.) The gemmule-spicules are regularly sausage-shaped.

TYPES in the Indian Museum.

HABITAT. Naukuchia Tal (alt. 4200 feet), Kumaon, W. Himalayas (S. W. Kemp).

Genus EPHYDATIA (p. 108).

After Ephydatia meyeni, p. 108, add:--

Ephydatia fluviatilis, auct.

? Ephydatia fluviatilis, Lamouroux, Encyclop. Méthod. ii, p. 327 (1824).

Spongilla fluviatilis, Bowerbank (partim), Proc. Zool. Soc. London, 1863, p. 445, pl. xxxviii, fig. 1.

Ephydatia fluviatilis, J. E. Gray (partim), Proc. Zool. Soc. London, 1867, p. 550.

Meyenia fluviatilis, Carter (partim), Ann. Nat. Hist. (5) vii, p. 92, pl. vi, fig. 11 a, b (1881).

Ephydatia fluviatilis, Vejdovsky, Abh. k. Böhm. Gesellschaft Wiss. xii, p. 24, pl. i, figs. 1, 2, 7, 10, 14, 19 (1883).

Ephydatia fluviatilis, id., P. Ac. Philad. 1887, p. 178.

Meyenia fluviatilis var. gracilis, Potts, ibid., p. 224.

Meyenia robusta, id., ibid., p. 225, pl. ix, fig. 5.

Ephydatia fluviatilis, Weltner, Arch. Naturg. Berlin, 1895 (i) p. 122.

Ephydatia robusta, Annandale, Journ. As. Soc. Bengal, 1907, p. 24, fig. 7.

Ephydatia fluviatilis, Weltner, in Brauer's Süsswasserfauna Deutschlands xix, Süsswasserschwämme, p. 185, figs. 316, 317 (1909).

Ephydatia fluviatilis, Annandale, P. U. S. Mus. xxxviii, p. 649 (1910).

This species only differs from E. meyeni in the following characters:--

(i.) there are no bubble-cells in the parenchyma;

(ii.) there is less spongin in the skeleton, which is less compact;

(iii.) the gemmule-spicules are longer, the shafts being as a rule longer than the diameter of the rotulæ;

(iv.) the gemmules are armed with a single row of regularly arranged spicules embedded in pneumatic tissue with minute air-spaces.

The sponge is a variable one and several "varieties" have been described from different parts of the world. My Indian specimens come nearest to the form described by Potts as Meyenia robusta, but have rather more slender skeleton-spicules and more elongate gemmule-spicules. The latter also appear to be less frequently "monstrous."

TYPE ?

GEOGRAPHICAL DISTRIBUTION.--E. fluviatilis is widely distributed in Europe and occurs in N. America, S. Africa (var. capensis, Kirkpatrick), Australia, and Japan. Specimens were obtained by Mr. Kemp from several lakes in Kumaon, namely Naukuchia Tal (alt. 4200 feet), Bhim Tal (4450 feet), Sat Tal (4500 feet), and Naini Tal (6300 feet). The gemmules from Bhim Tal referred by me to E. robusta (Potts) also belong to this species.

Biology. The external form of the sponge is due in great part to its environment. Specimens on small stones from the bottom of the Kumaon Lakes consist of thin disk-like films, often not more than a few centimetres in diameter and a few millimetres thick: others, growing on thin twigs, are elevated and compressed, resembling a cockscomb in appearance, while others again form nodules and masses of irregular form among the branches of delicate water-weeds. Some of these last are penetrated by zoaria of Fredericella indica.

Weltner has published some very interesting observations on the seasonal variation of minute structure in European representatives of the species (Arch. Naturg. Berlin, lxxiii (i), p. 273 1907) and has discussed the formation of the abnormal spicules that sometimes occur (ibid. lxvii (Special Number), p. 191, pls. vi, vii, figs. 27-59, 1901).

Genus CORVOSPONGILLA (p. 122).

After Corvospongilla burmanica, p. 123, add a new species:--

Corvospongilla caunteri, nov.

Sponge forming thin films of considerable area not more than 3 or 4 mm. thick, of a bright green colour, moderately hard but friable. The surface smooth; oscula inconspicuous, surrounded by shallow and ill-defined radiating furrows; a very stout basal membrane present.

A=Gemmule; B=gemmule-spicules; C=flesh-spicules; D=Skeleton-spicules.]

Skeleton reticulate but almost devoid of spongin, the reticulations close but formed mainly by single spicules; skeleton-fibres barely distinguishable. A close layer of spicules lying parallel to the basal membrane.

Spicules. Skeleton-spicules variable in size and shape, almost straight, as a rule smooth, moderately stout, blunt or abruptly pointed; sometimes roughened or spiny at the tips, often sharply pointed. Flesh-spicules minute, few in number, with smooth, slender shafts which are variable in length, never very strongly curved; the terminal spines relatively short, not strongly recurved. Gemmule-spicules amphistrongylous or amphioxous, irregularly spiny, slender, of variable length.

Gemmules free in the substance of the sponge, spherical or somewhat depressed, very variable in size but never large, having a thick external pneumatic coat in which the air-spaces are extremely small and, inside this coat, a single rather sparse layer of spicules lying parallel to the gemmule. A single depressed aperture present.

TYPE in the Indian Museum.

HABITAT. Hazratganj, Lucknow; on piers of bridge in running water (J. Caunter, 29-30. iv. 11).

The structure of the gemmules of this species differs considerably from that in any other known species of the genus, in which these structures are usually adherent and devoid of a true pneumatic coat. In some of the gemmules before me this coat measures in thickness about 1/9 of the total diameter of the gemmule. C. caunteri is the first species of Corvospongilla to be found in the Indo-Gangetic plain.