SPONGES. 

 By N. Annandai+e. 



The sponges of the Chilka L,ake, though few in number of species, are of great 

 biological interest, not merely because they consist of both freshwater and marine 

 forms growing together in an intimate manner, but also because at least one of the 

 latter has become modified in accordance with conditions of life more proper to an 

 inland lake than to any part of the sea, while the true freshwater sponge Spongilla 

 alba has developed peculiarities that are correlated with conditions only to be des- 

 cribed as marine. The following is a list of the species obtained in the course of our 

 survey. All are siliceous sponges belonging to the order Tetraxonida. 



MONAXONBIvLIDA. 



Fam. SpongiUvIDAE. Fam. Suberitidae. 



Spongilla alba, Carter. Suberites sericeus, Thiele. 



Spongilla nana, sp. nov. Laxosuberites aquae-dulcioris , 



Fam. Cijonidae. Annandale. 



Cliona vastifica, Hancock. Laxosuberites lacustris, sp. nov. 



TETR AXONELLID A . 



Fam. Tetiixidae. 



Tetilla dactyloidea (Carter) var, lingua, nov. 



With the exception of Spongilla nana, these seven sponges are common either 

 throughout or in parts of the lake. Spongilla alba, being apparently unable to live 

 in water that is distinctly brackish or salt at all seasons of the year, is found only in 

 the outer channel and in the northern part of the main area of the lake itself, but 

 flourishes in a pool of fresh water on an island in the southern part. Spongilla nana 

 was found, on one occasion only, in the northern part of the same area; it is possibly 

 no more than a modified form of the other species. The boring sponge Cliona vasti- 

 fica is abundant in oyster-shells in the outer channel and also occurs in those of Pur- 

 pura in Rambha Bay and the neighbourhood. Suberites sericeus and Laxosuberites 

 aquae-dulcions grow all over the lake, while L. lacustris has been found only in rocky 

 localities in the main area, and the Tetilla in sandy parts of the outer channel. 



We know at present, as I have recently pointed out elsewhere, 1 very little about 

 the littoral sponges of the Bay of Bengal, and the biological conditions that prevail 



1 Rec. Ind. Mus. X, p. 194 (1914). 



