This sponge is allied to S. bombayensis, from which it is distinguished not only by the abnormal characters of its gemmule-spicules and the absence of flesh-spicules, but also by the form of its skeleton-spicules and the structure of its skeleton. I have examined several specimens dry and in spirit; but S. ultima is the only Indian freshwater sponge, except Corvospongilla burmanica, I have not seen in a fresh condition.
Types in the Indian Museum; co-types at Trivandrum.
Habitat. Discovered by Mr. R. Shunkara Narayana Pillay, of the Trivandrum Museum, in a tank near Cape Comorin, the southernmost point of the Indian Peninsula.
Genus 2. PECTISPONGILLA, Annandale.
Pectispongilla, Annandale, Rec. Ind. Mus. iii, p. 103 (1909).
Type, Pectispongilla aurea, Annandale.
The structure of the sponge resembling that of Euspongilla or Ephydatia; but the gemmule-spicules bear at either end, at one side only, a double vertical row of spines, so that they appear when viewed in profile like a couple of combs joined together by a smooth bar.
Fig. 20.—Gemmule and spicules of Pectispongilla aurea (type specimen). a, Skeleton-spicules; b, gemmule-spicules; b', a single gemmule-spicule more highly magnified.
Geographical Distribution.—The genus is monotypic and is only known from Travancore and Cochin in the south-west of the Indian Peninsula.