1909.J R. E. Lloyd : The Races of Indian Rats. 15 



such as melanism, etc., commonly occur in family 

 groups. A family group may be defined as a small 

 part of a community the members of which resemble 

 one another very closely, so that the mean of their 

 characters is different from the mean of the charac- 

 ters in the^general community. Family groups prob- 

 ably arise owing to prepotency and inbreeding. The 

 term '* clan" ma:y be suitably applied to them, A 

 family group is originally a small community ; it 

 may, however, become a large one : it is then a race. 

 That a very small community may become a large 

 one, despite inbreeding, was shown by the Austrahan 

 rabbits. 

 These statements appear somewhat didactic ; they are of 

 course merely brief expressions of the writer's 

 opinion. (See Appendix II.) 



5. The word type is used by me in two senses. By the 



type of a species is meant an imaginary individual 

 which embodies the mean characters of the species. 

 By "type" of a species is meant the arbitrarily 

 chosen type specimen which is laid down for refer- 

 ence in some place, like a standard of measurement. 



6. The word species has many different shades of meaning ; 



it must however be used in referring to systematic 

 literature. A number of rats which closely resemble 

 one another and form a discontinuous group has been 

 generally spoken of as a race. 



SYSTEMATIC DESCRIPTION ACCORDING TO REGIONS. 



The Punjab. 



Owing to the energy of Captain G. I. Davj-s, I. M.S., it has 

 been possible to investigate the rats of the Punjab in a most satis- 

 factory manner. Although strenuously engaged on plague duty, 

 he has contrived to send us over 1,000 rats with careful measure- 

 ments of each. This large collection has been received in the form 

 of skins, including skulls, tails and feet, preserved in spirit. To 

 each skin is attached a metal plate referring to the measurements, 

 which were taken immediately after death b}' chloroform. This 

 is a very convenient method of transporting large numbers of 

 rats ; on arrival they can, if desired, be set up as dried specimens 

 in the conventional state in which small mammals are usually 

 found in museums. The colour of the fur is not altered by the 

 brief immersion in spirit. 



Among house rats, we have received 513 of the Mus rattus 

 type from fifty villages in the Amritsar district, 105 rats of the 

 same type from Lyallpur, and 55 white-bellied rats from three 

 specified villages. In addition, wc have received records of the 



