130 BULLETIN 99, UNITED STATES NATIONAL MUSEUM. 



ARVICANTHIS ABYSSINICUS NAIROBI Allen. 



1909. Arvicanthis nairobse Allen, Bull. Amer. Mus. Nat. Hist., vol. 26, p. 168, 

 March 19. (Nairobi, British East Africa; type in Amer. Mus. Nat. Hist., 

 New York.) 



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



ser. 8, vol. 4, p. 537. December. 



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



ed., pp. 473 and 478; London ed., pp. 485 and 490. 



Specimens. — Eighty-seven, from the following localities: 



British East Africa: Engare Narok River, 7 (Loring); Fort 

 Hall, 14, including 2 in alcohol (Loring, Mearns); Juja Farm, 44, 

 including 3 in alcohol and 8 odd skulls (Loring, Mearns); Lake 

 Naivasha, south end, 4 (Loring, Mearns); Nairobi, 1 (Mearns); 

 Nyeri, 1 (Loring); Ulukenia Hills, 16, including 6 in alcohol (Loring). 



Specimens collected near the south end of Lake Naivasha are 

 practically indistinguishable from the Nairobi and Juja Farm 

 skins. The range of nairohx extends also west to the Engare Narok 

 River, thus separating in this region the subspecies prseceps and 

 pallescens, on the north and south. Lonnberg ^ has recorded, on 

 Dollman's identification of a specimen, Arvicanthis abyssinicus 

 prseceps from Fort Hall. Specimens in our excellent series from Fort 

 Hall are in every way similar to nairohx rather than to prseceps, and 

 the record of prseceps from Fort Llall, based on a single specimen, is 

 doubtless erroneous. 



Loring found two females at Juja Farm, May 16, with six fetuses 

 each. Mearns records from the same locality one female with six 

 large fetuses. May 23, and one with three fetuses. May 24. 



Roosevelt and Heller say of this species:^ 



The commonest mouse in B. E. A. on the plains. Outnumbers any other species. 

 Found everywhere in grass and brush, but not in deep forest. Often lives in shallow 

 burrows round the bases of thorn-trees, from which its well-marked runways radiate 

 into the grass. Strictly diurnal. Often seen running about in bright sunlight. Never 

 found in traps at night. 



ARVICANTHIS ABYSSINICUS PR/ECEPS Wroughton. 



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

 ser. 8, vol. 4, p. 538. December. (Naivasha, British East Africa; type 

 in British Museum.) 



Specimens. — Seven, from the following localities: 

 British East Africa : Mayo River, Laikipia, 3 (Heller) ; Naivasha 

 Station, 4, including 1 in alcohol and 1 odd skull (Loring, Mearns). 



ARVICANTHIS ABYSSINICUS PALLESCENS Dollman. 



1914. Arvicanthis rumruti pallescens Dollman, Abstract Proc. Zool. Soc. London, 

 No. 131, p. 25. April 14. (Loita Plains, British East Africa; tj-pe in 

 British Museum.) 



1 Kungl. Svenska Vet. Akad. Handl., vol. 48, No. 5, p. 99. 1912. 



2 African Game Trails, Appendix B, p. 478. 1910. 



