84 THE GROWTH OF GROUPS 



one of the three villages where white-bellied rats were 

 obtained ; but these two specimens have, in addition to 

 albiventralism, other peculiar characters. They both 

 have a white patch or " star " in the middle of the fore- 

 head and the terminal third of the length of the tail is 

 pure white. Besides this, the general colour of the fur is 

 of a peculiar light hue which is perhaps identical with that 

 known as " silver fawn " in mice. Wild rats of this 

 peculiar tint are rare, but they fyave been seen on other 

 occasions. This remarkable pair, for they are male and 

 female, are nearly of the same size. In this respect both 

 are well below the mean body weight as calculated in 

 the rats of the district. They weighed 85 and 95 grams, 

 the mean being 140 grams. The measurements which 

 provide us with this information were made immediately 

 after the death of the animals, as a routine, by one who 

 did not know why the measurements were required. 



The interest of the case lies wholly in the similarity 

 between the two specimens. It is fortunate that two 

 of them were captured. If only one had been obtained 

 we could have learnt nothing from it, it must have been 

 regarded as a freak and passed over. But the fact that 

 there were two of them, as like one another as it is 

 possible for two organisms to be, arouses the attention 

 and suggests that they are part of a species. On sending 

 them, their finder gave it as his opinion that they were a 

 new species, and suggested the name Mus brahminicus, 

 on account of the white mark on the forehead. If a 

 number of them had been sent together to a museum, 

 unaccompanied by information as to their circumstances, 

 they would have been regarded doubtfully as a new 

 species, but if others had been sent at a later date the 



