XXVII.— N O T E S ON FRESHWATER vS P O N G E S. 

 By N. Annandai^e, B.A., D.Sc, Superintendent, Indian Museum 



VI. — The midday siesta of Spongilla in the Tropics. 



During last winter I was able to keep specimens of Spon- 

 gilla c assissima and 5. prolif evens alive for some weeks in an 

 aquarium. Accidentally, while attempting to demonstrate the 

 currents set up in the water by their activit}', I discovered that 

 for some hours in the middle of the day these currents ceased. 

 During their cessation the oscular collars were considerabh^ con- 

 tracted but not altogether closed, but I have been able to obtain 

 no evidence that the cells that surround the inhalent pores have 

 the power of contraction at all well developed. The cessation of 

 the currents can, therefore, have been due onl}" to cessation of move- 

 ment on the part of the flagellae of the collar cells. It is b3^ 

 no means uncommon for coelenterates to remain in a state of 

 quiescence during the heat of the day in the tropics and even 

 in temperate climates, and it is not surprising that sponges should 

 follow the same' course. The great majorit}" of the organisms found 

 in ponds in Lower Bengal appear to be adversely affected by 

 heat and, as it were, imperfectly acclimatized. Winter is the onl^?- 

 time at which many of them flourish, although this is by far 

 the driest season in Calcutta, and the majorit}^ are most active 

 in the evening and early morning. 



VII. — Description o7 two new Freshwater Sponges from 

 Eastern Bengal, with Remarks on allied Forms. 



The two new sponges here described were found at Rampur 

 BhooHa (Rajshahi), Eastern Bengal, in February last. Both of 

 them were abundant on reeds and twigs, together with Spongilla 

 carteri, Bowerbank, in several ponds near the European quarter of 

 the town. 



Spongilla reticulata, (?) sp. nov. 

 Subgenus Euspongilla, Vejdovsky. 



Sponge soft, consisting of a thin layer incrusting the support, 

 and of numerous transversely elongated, laterally compressed, 

 delicate branches, which frequently anastomose so as to form 

 a reticulated structure. Colour bright green. Surface smooth, 

 minutel}" hispid ; oscula surrounded by conspicuous mem- 

 branous collars, which are supported by a delicate ring of 

 spongin ; pores minute. Primary radiating fibres of skeleton 

 delicate, feebly coherent, never with more than a few spicules 

 parallel to one another, secondary (transverse) fibres barely 

 distinguishable as such, irregular ; the whole skeleton ex- 



