84 Records of the Indian Museum. [Voy. XVIII, 
southern Palaearctic, partly cosmopolitan. ‘The Indian element 
is strongest, or at any rate most conspicuous, in the Polyzoa. 
It is remarkable to find these groups (or at any rate the spon- 
ges and Polyzoa) so well represented in a country that seems in 
almost every respect unsuitable for them. In the Inlé lake- 
system in the Shan States,! a district apparently in all respects 
favourable to such organisms, only three sponges and two Polyzoa, 
both of which belonged to the same genus, were found ; whereas 
in the Hamun system, in which the water is of extremely variable 
composition and amount, in which extremes of climate occur in 
regular succession, the same number of sponges and twice as many 
Polyzoa (which belonged, moreover, to three genera) were ob- 
tained. It might seem at first sight that it was necessary for gem- 
mules and statoblasts to undergo desiccation, of which there is 
the greatest possible chance in Seistan, just as it is necessary 
for the eggs of many “ Phyllopod’’ Crustacea; but against this 
theory must be placed the richness of the fauna of these groups 
in the comparatively equable conditions of Lower Bengal. We 
are still far from understanding the factors that encourage growth 
and reproduction in the lower aquatic invertebrates, and the only 
possible way to gain light is to keep careful records of the modes of 
occurrence of the living animals and of the provenance of specimens. 
The Hamun is the seventh large Asiatic lake that I have had an 
opportunity of examining in the last seven years (as well as innu- 
merable smaller bodies of water), and in each place I have paid 
particular attention to the sponges and Polyzoa; but I must con- 
fess myself still as far as ever from understanding many of the 
fundamental factors in the biology of these groups. The lakes 
have been of diverse kinds and situated in diverse countries—Lake 
Biwa in Japan, the Tai Hu in China, the Talé Sap in Siam, the 
Inlé Lake in Burma, the Chilka Lake in India, the Hamun in 
Persia and the Take of Tiberias in Palestine. But they are not 
sufficient. 
PORIFERA, 
Of three sponges collected in Seistan in winter, one (Ephy- 
datia fluviatilis) was found in an active state; of one ofthe others 
only dried specimens were found, and of the third only gemmules. 
The Ephydatia is interesting because it occurred in the Hamun-i- 
Helmand in two phases each correlated with a different type of 
environment. 
I take this opportunity to describe’a new variety of Spongilla 
lacustris from Mesopotamia. 
Spongilla alba, Carter. 
1915. Spongilla alba, Annandale, Mem. Ind. Mus. V, pp. 25-32, figs. 1, 2 
pl. play, figs. a2 pl. wv, hie: a. 
' Annandale, Rec, Jnd. Mus, X1V, p. 75 (1918). 
