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voy ay 5.| Notes on the Freshwater Fauna of India. 195 
They consist of a pair of tubular structures which closely resem- 
ble the antenne in outward appearance, except that they are 
not jointed. ach is really double. ‘heir function is evidently 
obtain nourishment by suction; but it is not known whether 
the European form feeds on the Sponge or on other animals or 
plants, and I have no observations on this point to offer as regards 
the Indian larva. 
ave only found this larva during the winter months. 
Unlike its Europeam congener, it is not confined to the natural 
cavities of the Sponge ; for it forces its way into the actual sub- 
stance of its host. 
of hardship for aquatic animals, owing tv scarcity of food and the 
formation of ice; whereas in Calcutta the high temperature to 
which water, and especially shallow, stagnant water, rises i 
the hot season, appears to inimical to most forms of animal 
life, while life flourishes in the comparatively, but not actually 
cold water of the cool season. In Calcutta few of the “ tanks ” 
so recent as Lower Bengal. ed from a geological stand- 
point, the animals of this part of the country are, without exception, 
recent immigrants, and we find that some characteristic represen- 
tatives of even the Indian terrestrial fauna (e.g., Ohameleon calcara- 
tus and Sitana ponticeriana) have never managed to establish them- 
selves in the Ganges delta, Aquatic animals can usually adapt 
themselves to changed conditions, as we see by comparing the 
fauna of a Calcutta “tank ” and that of a British pond and not- 
animals of the Calcutta “tanks” towards the end of March, is 
separated than they are in Lower Bengal. 
SuMMARY. 
At least two species of Dipterous larve, a Beetle larva, a 
Neuropterous larva of the genus Sisyra, and a Worm probably 
belonging to the genus Chetogaster, occur in the substance of 
