CHAPTER V 



THE next case to be presented is in one respect of less 

 weight than the foregoing, because the number of indi- 

 viduals exemplifying the group is only two, but it is of 

 interest since the peculiarity in virtue of which the two 

 specimens are marked off from the normal multitude 

 appears as a number of separate characters. They have 

 therefore that relationship to one another which is com- 

 monly regarded as the relationship between members of 

 a species, and they are related to the rest of the animal 

 kingdom as the members of a species are related to all 

 animals that are not of that species. 



The nature of the normal multitude among which the 

 two abnormal ones were found is satisfactorily known. 

 Reference has already been made to investigations which 

 were carried out in the Amritzar district of the Punjaub. 

 There the character of the rat population was ascertained 

 in sixty-two villages. In only three of these villages 

 were white-bellied rats found, and at one of them, Nowshera 

 Dhala by name, nine hundred rats in all were captured, 

 including the two sports now to be described. 



They both possess the following peculiarities. The 

 complete character of albiventralism, i.e. the lower jaw, 

 throat, breast, belly, and the inside of the limbs is 

 covered with pure white fur, which is sharply marked off 

 from the coloured fur of the sides. Nowshera Dhala is 



