THE GROWTH OF GROUPS 81 



have finally to be considered as but one species." In 

 regard to the colour of the common Indian rat, he says, 

 " Colour varying from dark rufous-grey to bright reddish 

 fulvous, belly sometimes quite white, sometimes no 

 lighter than the back." He makes no statement as to 

 which kind is the commoner. 



Hence taxonomists hold that the rodents common 

 in Indian houses constitute a species, the members of 

 which may either be whole-coloured or white-bellied. 

 That is to say, in their opinion either kind may give birth 

 to the other, and they may interbreed. 



In some parts of India the white-bellied rats predomi- 

 nate in number over the others. This is the case at 

 Tellicherri. The forty-eight specimens from that place 

 were sent on four occasions, but on each occasion the 

 number of the white-bellied kind was in excess of 

 the other. There can be no doubt that the former 

 predominates in Tellicherri. 



So far we have been considering only animals caught 

 in the main body of the Peninsula and have not men- 

 tioned those of the Himalayas, the well-known range of 

 mountains which form the northern boundary of India. 

 The rats of several towns situated among these mountains 

 were investigated. Nearly all from Sirinagar, Simla, and 

 Nainital are white bellied. It is necessary to say nearly 

 all, for out of about fifty specimens from each of these 

 places there were exceptions in each case. There is no 

 certain relation between altitude and colour, for the rats of 

 mountainous regions, such as Darjiling, Khatmundu, and 

 Ootacamund are whole coloured ; conversely, white-bellied 

 rats are established in some lowland districts, as, for ex- 

 ample, in Tellicherri and Rangoon. 



G 



