Types of both the typical form and the variety in the Indian Museum; co-types of the typical form in the Trivandrum Museum.
Geographical Distribution.—The same as that of the genus. Localities:—Tenmalai, at the base of the western slopes of the W. Ghats in Travancore (typical form) (Annandale); Ernakulam and Trichur in Cochin (var. subspinosa) (G. Mathai).
Biology.—My specimens, which were taken in November, were growing on the roots of trees at the edge of an artificial pool by the roadside. They were in rather dense shade, but their brilliant golden colour made them conspicuous objects in spite of their small size. Mr. Mathai's specimens from Cochin were attached to water-weeds and to the husk of a cocoanut that had fallen or been thrown into the water.
Genus 3. EPHYDATIA, Lamouroux.
Ephydatia, Lamouroux, Hist. des Polyp. corall. flex.* p. 6 (fide Weltner) (1816). Ephydatia, J. E. Gray, P. Zool. Soc. London. 1867, p. 550. Trachyspongilla, Dybowsky (partim), Zool. Anz. i, p. 53 (1874). Meyenia, Carter (partim), Ann. Nat. Hist. (5) vii, p. 90 (1881). Carterella, Potts & Mills (partim), P. Ac. Philad. 1881, p. 150. Ephydatia, Vejdovsky, Abh. Böhm. Ges. xii, p. 23 (1883). Meyenia, Potts (partim), ibid. 1887, p. 210. Carterella, id. (partim), ibid. 1887, p. 260. Ephydatia, Weltner (partim), Arch. Naturg. lxi (i), p. 121 (1895). Ephydatia, Annandale, P. U.S. Mus. xxxvii, p. 404 (1909).
Type, (?) Spongilla fluviatilis, auctorum.
This genus is separated from Spongilla by the structure of the gemmule-spicules, which bear at either end a transverse disk with serrated or deeply notched edges, or at any rate with edges that are distinctly undulated. The disks are equal and similar. True flesh-spicules are usually absent, but more or less perfect birotulates exactly similar to those associated with the gemmules are often found free in the parenchyma. The skeleton is never very stout and the skeleton-spicules are usually slender.
As has been already stated, some authors consider Ephydatia as the type-genus of a subfamily distinguished from the subfamily of which Spongilla is the type-genus by having rotulate gemmule-spicules. The transition between the two genera, however, is a very easy one. Many species of the subgenus Euspongilla, the typical subgenus of Spongilla (including S. lacustris, the type-species of the genus), have the spines at the ends of the gemmule-spicules arranged in such a way as to suggest rudimentary rotules, while in the typical form of S. crateriformis this formation is so distinct that the species has hitherto been placed in the genus Ephydatia (Meyenia), although in some sponges that agree otherwise with the typical form of the species the gemmule-spicules are certainly not rotulate and in none do these spicules bear definite disks.
Geographical Distribution.—Ephydatia, except Spongilla, is the most generally distributed genus of the Spongillidæ, but in most countries it is not prolific in species. In Japan, however, it appears to predominate over Spongilla. Only one species is known from India, but another (E. blembingia*, Evans) has been described from the Malay Peninsula, while Weber found both the Indian species and a third (E. bogorensis*) in the Malay Archipelago.
16. Ephydatia meyeni* (Carter).