I9I5-] 



Fauna of the Chilka Lake : Sponges. 



31 



and many of them are retained in situ, for the skeleton is rarely destroyed completely 

 ere the return of the waters. In the pond on Barkuda Id. only dead sponges 

 were found in April ; in July the gemmules were beginning to sprout, and in September 

 the sponges were in full activity, new gemmules being formed. A mass of sprouting 

 gemmules kept in a dish of water on the island in July produced in five days a 

 small sponge with a single osculum. It is worthy of note that they did not each 

 produce a different ' ' individual " , but built, as it were, a single edifice in common. 

 The sponge is in full vigour in the lake in November and continues in this condi- 

 tion until the rocks on which it grows become dry or the water round them grows foul 

 owing to the decay of vegetation. As late as the beginning of March some extremely 



Fig. 3. — Spongilla nana, sp. nov. 

 Spicules of one of the type-specimens, x 255. 



hard living specimens were obtained on a little rock out in the lake near Patsahanipur. 

 The water was free from decaying weeds and covered a considerable depth of rock. 

 The earliest date at which we saw sponges of the species in a vigorous condition 

 was the end of September ; a large specimen was obtained a few days before the end 

 of that month on a reed at Nalbano Id. in 1913. The sponges taken in March (in 

 water of a specific gravity sometimes as high as 1-0065) contained many mature 

 embryos and young larvae as well as gemmules. The two kinds of reproductive body 

 were evidently produced in close proximity. 



The canals of 5. alba L often give shelter to large numbers of small animals of 



1 Faun. Brit. Ind., Freshw. Sponges p. 76 (191 1). 



