IQI5-] Fauna of the Chilka Lake : Sponges. 53 



var. lingua, nov. 



(Plate v, fig. 4). 



The var. lingua differs from the forma typica of the species in the following 

 characters : — 



1. The sponge is tongue-shaped and compressed instead of being sausage-shaped. 



2. The minute spherical spicules found by Keller in Carter's specimens from 



Arabia (the types of the species) are absent. 



3. The basal tuft of spicules is much reduced, being visible to the naked eye 



merely as a slight shagginess. 



4. The single osculum at the central cavity of the sponge is even smaller, or 



perhaps capable of more complete contraction. 



5. 'The pores are apparently confined to the upper three quarters of the super- 



ficial area of the sponge. 



I have been able to compare our specimens with several of those from the 

 Mergui Archipelago examined by Carter. As Sollas has pointed out, the latter do 

 not altogether agree with the original specimens and I cannot find in them, any more 

 than in the types of the new variety, the minute siliceous spheres found by Keller in 

 Carter's Arabian examples. 



The sponges from the Chilka Lake agree well in general structure with those 

 from Mergui, from which they differ notably in their compressed, tongue-like shape 

 and in the still greater reduction of the basal tuft. The spicules, except that those 

 of the basal tuft are of course much shorter, appear to be practically identical. 

 The osculum is more completely closed and the central cavity into which it opens 

 almost obliterated. The fact, however, that the external surface is thrown in the 

 larger specimens into strong vertical folds in the anterior part of the body, and 

 the manner in which these folds radiate from the osculum, would indicate that the 

 sponges were killed in a highly contracted state. The shape of the posterior end is 

 somewhat variable, this extremity being tapering and rounded in some sponges and 

 obliquely truncate in others. In the latter there is no trace of external injury. The 

 largest, which has this shape, is 58 mm. long and 22 mm. broad in the middle, where 

 it is 10 mm. thick. This specimen is less compressed in the anterior region than 

 the others. A photograph of it, with one of a smaller example from the same sta- 

 tion, is reproduced on plate v, fig. 4. The colour of the sponge (in life and in spirit) 

 is pale greenish grey. 



Specimens of T. dadyloidea var lingua were taken in the outer channel of the 

 Chilka Lake in September, 191:4, at depths of about 2 fathoms. All were on a sandy 

 bottom. The water at the time was fresh, but there can be little doubt that the 

 sponge is also to be found at the same place when it is salt. It evidently lived in 

 groups at more than one point. 



The species has always been taken in shallow water apparently anchored in sand 

 by its basal tuft. The reduction of this tuft is probably correlated with the com- 

 pressed form of the new variety, and both characters, as well as the position of the 



