THE BLACK OR SHIP RAT 



593 



the group in three sub-groups or varieties ; he used the name alexan- 

 drinus for all the Indian forms of rattus, and stated that the "typical 

 form," characterised by its large size, long tail, and coloration (dark 

 rufous grey above, white below), inhabited Kashmir and the whole 

 north-western region of India. 



A somewhat similar arrangement was later adopted by Bonhote 

 {Fascic. Malay., Zool., i., 32, 1903 ; and Proc. Zool. Soc, London, 1910, 

 653), who recognised three sub-groups of Oriental rattus as follows : — 



(i) The jaloreusis sub-group, of which E. jalorensis, Bonhote, 

 from Jalor, Perak, and Siam, is the type. These are hill-rats repre- 

 senting the nitidus group of Thomas and other authors, and they 

 have the hairs of the under parts white to their bases, and a hind foot 

 length of about 30 mm. The sub-group has a wide but discontinuous 

 distribution in India and Malaya. 



(2) The rufe3cens sub-group, of which E. rufescens, Gray, from 

 Dharwar, is the type. These are tree-rats, and have the hairs of the 

 under parts with white or yellowish tips, and slate-coloured bases, 

 and a hind foot length of about 33 mm. This sub-group is found 

 throughout the whole of continental India, except the north-western 

 part, and in Ceylon. In some provinces and in Ceylon a variety with a 

 pure white belly is found side by side with typical rufescens, but in 

 Burma and Tenasserim the white-bellied form alone occurs (Wroughton, 

 /. Bombay N. H. Soc, 23, 474 and 715). From Simla, Bonhote has 

 described E. vicerex, a member of the group with striking bicoloration 

 of the tail and white feet. 



(3) The griseiventer sub-group, of which E. griseiventer, Bonhote, 

 from Perak, is the type. These are chiefly house-rats, and in them the 

 ventral hairs are either entirely slate-coloured or else have fulvous tips, 

 and the hind foot measures about 35 mm. This sub-group has a wide 

 distribution throughout India, Ceylon, and the Malay peninsula and 

 islands. 



Hossack {Mem. Indian Museum, i., 1-80, 1907) studied the rats of 

 Calcutta in connection with plague ; his material led him to regard 

 the distinctions between the races of rattus recognised by Bonhote as 

 quite inconstant and sporadic, and he therefore denied that such 

 characters have any systematic importance. Bonhote {Proc. Zool. Soc, 

 London, 1910, 653), in answer to Hossack, states that in the large 

 towns, whence all Hossack's material came, no order or classification 

 is possible, because the varieties have become hopelessly mixed and 

 crossed, but that in the country districts the varieties are much better 

 defined, and apparently breed true ; '' all these varieties of the long- 

 tailed rat belong to one species, Mus rattus^ Meanwhile Lloyd 

 (Rec Indian Museum, iii., i-ioo, 1909) studied a very large number 

 of rats from India and Burma ; his work was a continuation of that 



