70 THE GROWTH OF GROUPS 



is, therefore, preferable to use the term white-bellied 

 kind. The map on page 69 shows how far this variety 

 was established in the city of Poona ; it must be remem- 

 bered that forty-five thousand whole-coloured rats have 

 been taken from the city at large, and that there is scarcely 

 a house which has not contributed to the total. The 

 nineteen white-bellied rats were caught in nine houses ; 

 four of these are contiguous and two others are separated 

 from them by the width of a street. Six of the houses 

 therefore form a distinct focus of habitation for rats of this 

 special variety. The other three houses form another 

 centre, perhaps more than one, which is situated about 

 250 yards further south. 



The following table is taken from the register, and shows 

 the order in which the rats were captured. No steps 

 were taken to ascertain the distribution of the white- 

 bellied rats, but nevertheless the facts concerning their 

 whereabouts came to light of their own accord, for the 

 register shows that whenever during the year a white- 

 bellied rat was captured it was out of a house belonging 

 to the group indicated on the map. 



The focus which is represented by six houses, 379-382, 

 553, and 963, Raiwar, contributed fourteen rats, but, as 



