EAST AFRICAN MAMMALS IN ISTATIONAL MUSEUM. 129 



and by its shorter tail. In its blackish coloration it much resembles 

 certain specimens of A. ahyssinicus nuhilans of the Kisumu Province, 

 British East Africa, but its distribution is separated from the range of 

 that form by the Uganda A. a. rubescens, which occupies the eastern 

 side of the Nile system from Ankole to southern Sudan (Mongalla 0. 



ARVICANTfflS ABYSSINICUS RUBESCENS Wroughton. 



909. Arvicanthis abyssinicus rubescens Wroughton, Ann. and Mag. Nat. Hist, 

 ser. 8, vol. 4, p. 539. December. (Kibero, Unyoro, Uganda; type in 

 British Museum.) 



1910. Arvicanthis abyssinicus rubescens Roosevelt, African Game Trails, Amer. 



ed., p. 473; London, ed., p. 485. 



1911. [Arvicanthis] rubescens Heller, Smithsonian Misc. Coll., vol. 56, No. 17, 



p. 10. February 28. (Part; specimens from Gondokoro, Uganda.) 



Specimens. — Seventeen, from localities as follows: 

 Uganda: Butiaba, 1 (Loring); Gondokoro, 9, including 1 in 

 alcohol (Loring); Hoima, 1 (Loring); Kampala, 3 (Loring); Kisingo, 

 2 including 1 in alcohol (Loring); Nimule, 1 in alcohol (Heller). 



There is considerable variation in color among the specimens 

 representing this form, but on the average they are lighter and more 

 reddish than any specimens of the neighboring subspecies in Lado and 

 about Kavirondo Gulf. The Nile appears to be an effective barrier 

 between this form and the much darker subspecies of Lado. 



ARVICANTHIS ABYSSINICUS NUBILANS Wroughton. 



1909. Arvicanthis abyssinicus nubilans Wroughton, Ann. and Mag. Nat. Hist., 

 ser. 8, vol. 4. December. (Kisumu, British East Africa; type in 

 British Museum.) 



Specimens. — Forty-five, from the following localities: 



British East Africa : Kaimosi, 23, including 5 in alcohol (Heller, 

 Turner); Kakumega, 2 (Heller); Kisumu, 18, including 3 in alcohol 

 (Heller, Turner) ; Nzoia Kiver, 1 (Heller) ; Sirgoit Lake, 1 in alcohol 

 (Heller). 



This is a very slightly characterized form, averaging a little darker 

 than A. a. rubescens. The amount of variation between specimens 

 from Kisumu and Kaimosi is, however, almost as great as between 

 the race as a whole and rubescens, and I much doubt if a conscientious 

 reviser, working with suitable series of specimens, will recognize more 

 than one form in the Nyanza region. I have been able to find only 

 one character on which to justify the separation of the two subspecies, 

 the slightly larger molar teeth of nubilans. This difference is pro- 

 nounced when comparison is made between rubescens and specimens 

 of nubilans from Kisumu, but much less so if specimens of the latter 

 from Kaimosi are used. 



Heller found five embryos in a female collected at Kaimosi 

 January 23. 



' Recorded by Wroughton, Ann. and Mag. Nat. Hist., ser. 8, vol. 8, p. 461. October, 1911. 



