_Spicules._ Skeleton-spicules entirely smooth, moderately stout, feebly curved, sharply pointed. No flesh-spicules. Gemmule-spicules with the shaft as a rule moderately stout, much longer than the diameter of one disk, smooth or with a few stout, straight horizontal spines, which are frequently bifid or trifid; the disks flat, of considerable size, with their margins cleanly and deeply divided into a comparatively small number of deep, slender, triangular processes of different sizes; the shaft extending not at all or very little beyond the disks. _Gemmules_ spherical, usually numerous and of rather large size; each covered by a thick layer of minute air-spaces, among which the gemmule-spicules are arranged vertically, often in two or even three concentric series; a single short foraminal tubule; the pneumatic coat confined externally by a delicate membrane, with small funnel-shaped pits over the spicules of the outer series. I think that the gemmules found by me in Bhim Tal and assigned to Potts's _Meyenia robusta_ belong to this species, but some of the spicules are barely as long as the diameter of the disks. In any case Potts's description is so short that the status of his species is doubtful. His specimens were from N. America. _E. meyeni_ is closely related to the two commonest Holarctic species of the genus, _E. fluviatilis_ and _E. mülleri_, which have been confused by several authors including Potts. From _E. fluviatilis_ it is distinguished by the possession of bubble-cells in the parenchyma, and from _E. mülleri_ by its invariably smooth skeleton-spicules and the relatively long shafts of its gemmule-spicules. The latter character is a marked feature of the specimens from the Malay Archipelago assigned by Prof. Max Weber to _E. fluviatilis_; I am indebted to his kindness for an opportunity of examining some of them. TYPE in the British Museum; a fragment in the Indian Museum. GEOGRAPHICAL DISTRIBUTION.--India and Sumatra. _Localities_:--BENGAL, Calcutta and neighbourhood (_Annandale_); MADRAS PRESIDENCY, Cape Comorin, Travancore (_Trivandrum Mus._): BOMBAY PRESIDENCY, Island of Bombay (_Carter_): HIMALAYAS, Bhim Tal, Kumaon (alt. 4,500 feet) (_Annandale_). BIOLOGY.--My experience agrees with Carter's, that this species is never found on floating objects but always on stones or brickwork. It grows in the Calcutta "tanks" on artificial stonework at the edge of the water, together with _Spongilla carteri_, _S. alba_, _S. fragilis_ subsp. _calcuttana_, and _Trochospongilla latouchiana_. It flourishes during the cold weather and often occupies the same position in succeeding years. In this event the sponge usually consists of a dead base, which is of a dark brownish colour and contains no cells, and a living upper layer of a whitish colour. The larva of _Sisyra indica_ is sometimes found in the canals, but the close texture of the sponge does not encourage the visits of other _incolæ_. Genus 4. DOSILIA, _Gray_.