Biology.—There is a remarkable difference in external form between the specimens taken in Igatpuri and those from Nasik, and this difference is apparently due directly to environment. In the lake, the waters of which are free from mud, the sponges were growing on the lower surface of stones near the edge. They formed small crusts not more than about 5 cm. (2 inches) in diameter and of a pale greyish colour. Their surface was flat or undulated gently, except round the oscula where it was raised into sharply conical eminences with furrowed sides. The specimens from Nasik, which is about 30 miles from Igatpuri, were attached, together with specimens of Spongilla cinerea and S. indica, to the sides of a stone conduit full of very muddy running water. They were black in colour, formed broad sheets and were markedly corrugated on the surface. Their oscula were not raised on conical eminences and were altogether most inconspicuous. The skeleton was also harder than that of sponges from the lake.
In the lake C. lapidosa was accompanied by the gemmules of Spongilla bombayensis, but it is interesting that whereas the latter sponge was entirely in a resting condition, the former was in full vegetative vigour, a fact which proves, if proof were necessary, that the similar conditions of environment do not invariably have the same effect on different species of Spongillidæ.
[W] O. von Linstow, Rec. Ind. Mus. i, p. 45 (1907).
[X] W. M. Tattersall, ibid., ii, p. 236 (1908).
[Y] T. R. R. Stebbing, ibid., i, p. 160 (1907); and N. Annandale, ibid., ii, p. 107 (1908).
[Z] Mr. Stebbing has been kind enough to examine specimens of this isopod, which he will shortly describe in the Records of the Indian Museum. S. walkeri, its nearest ally, was originally described from the Gulf of Manaar, where it was taken in a tow-net gathering (see Stebbing in Herdman's Report on the Ceylon Pearl Fisheries, pt. iv, p. 31 (1905)).
[AA] See M. and A. Weber in M. Weber's Zool. Ergeb. Niederl. Ost-Ind. vol. i, p. 48, pl. v (1890).
[AB] Mr. C. A. Paiva, Assistant in the Indian Museum, has lately (March 31st, 1911) obtained specimens of S. crateriformis in a small pond of fresh water on Ross Island in the Andaman group. The existence of this widely distributed species on an oceanic island is noteworthy.
[AC] The only complete European specimen of the species I have seen differs considerably in outward form from any Indian variety, consisting of a flat basal area from which short, cylindrical turret-like branches arise. This specimen is from Lake Balaton in Hungary and was sent me by Prof. von Daday de Dees of Buda-Pesth.
[AD] Needham. Rec. Ind. Mus. iii, p. 206 (1909).