316 COMMON BEASTS OF AN INDIAN GARDEN 



explains the origin of their common Hindi name, 

 susu. They do not usually appear in herds, as so 

 many of their relatives do, but sometimes the river 

 seems full of individual specimens, all following 

 independent tracks. Now and then, however, and 

 particularly in parts of the stream where the con- 

 fluence of several currents has led to the formation 

 of deep, eddying pools, a troop will gradually con- 

 gregate and remain diving and circling around for a 

 considerable time. The re-appearance of the dolphins 

 in the river about Calcutta is one of the regular 

 harbingers of the end of the rainy season and the 

 approach of winter ; for, so long as the stream 

 is in full flood from the melting of Himalayan snow 

 and the monsoon drainage, they are never to be 

 seen in the Hugli. This is probably in great part 

 owing to the fact that during the time of their 

 absence the water-way at their disposal farther inland 

 is, for the time being, very greatly increased. Some 

 local factor, however, would also seem to come 

 into play, as they certainly sometimes abound in 

 the main stream of the Ganges between Damukdia 

 and Sara-ghat in the middle of August, at times 

 when the river is in full flood, and at a part of its 

 course comparatively very low down and near the 

 sea. They give the fishermen in the Hugli a good 

 deal of trouble by following fish into their nets, and 

 becoming entangled in them, where they are soon 

 drowned, but, in their dying struggles, manage to 



