_Trochospongilla latouchiana_, Annandale, J. Asiat. Soc. Bengal, 1907, p. 21, fig. 5. _Trochospongilla latouchiana_, _id._, Rec. Ind. Mus. ii, p. 157 (1908). _Trochospongilla leidyi_, _id._ (_nec_ Bowerbank), _ibid._ iii, p. 103 (1909). [Illustration: Fig. 24.--_Trochospongilla latouchiana._ Vertical section of part of skeleton with gemmules _in situ_, × 30; also a single gemmule, × 70. (From Calcutta).] _Sponge_ forming cushion-shaped masses rarely more than a few centimetres in diameter or thickness and of a brown or yellow colour, hard but rather brittle; surface evenly rounded, minutely hispid; oscula inconspicuous, small, circular, depressed, very few in number; external membrane adhering closely to the parenchyma; a chitinous membrane at the base of the sponge. Larger sponges divided into several layers by similar membranes. _Skeleton_ dense, forming a close reticulation; radiating fibres slender but quite distinct, running up right through the sponge, crossed at frequent intervals by single spicules or groups of spicules. _Spicules._ Skeleton-spicules smooth, about twenty times as long as the greatest transverse diameter, as a rule sharply pointed; smooth amphistrongyli, which are often inflated in the middle, sometimes mixed with them but never in large numbers. No flesh-spicules. Gemmule-spicules with the rotulæ circular or slightly asymmetrical, flat or nearly flat, marked with a distinct double circle as seen from above, sometimes not quite equal; the shaft not projecting beyond them; the diameter of the rotule 4-1/2 to 5 times that of the shaft, which is about 2-2/3 times as long as broad. _Gemmules_ small (0.2 × 0.18 mm.), as a rule very numerous and scattered throughout the sponge, flask-shaped, clothed when mature with a thin microcell coat in which the birotulates are arranged with overlapping rotulæ, their outer rotulæ level with the surface; foraminal aperture circular, situated on an eminence. _Average Measurements._ Diameter of gemmule 0.2 × 0.18 mm. Length of skeleton-spicule 0.28 " Length of birotulate-spicule 0.175 " Diameter of rotula 0.02 " _T. latouchiana_ is closely related to _T. leidyi_ (Bowerbank) from N. America, but is distinguished by its much more slender skeleton-spicules, by the fact that the gemmules are not enclosed in cages of megascleres or confined to the base of the sponge, and by differences in the structure of the skeleton. TYPE in the Indian Museum. GEOGRAPHICAL DISTRIBUTION.--Lower Bengal and Lower Burma. _Localities_:--BENGAL, Calcutta and neighbourhood (_Annandale_): BURMA, Kawkareik, Amherst district, Tenasserim (_Annandale_).