128 BULLETIN 99, UNITED STATES NATIONAL MUSEUM. 



The unstriped grass rats of the restricted * genus Arvicantliis are 

 well represented in the collections from nearly all the districts of 

 East Africa covered by our expeditions. The animals seem to be 

 abundant everywhere and good series of specimens of most of the 

 known forms were taken. 



For measurements of specimens of Arvicanthis see pages 132-135. 



ARVICANTHIS TESTICULARIS TESTICULARIS (Sundevall). 



1843. Tsomys testiculars Sukdevall, K. Svenska Akad. Handl., 1842, p. 221. 



(Bahr el Abiad, Sudan.) 

 1905. Arvicanthis testicularis Schwann, Nov. Zool., vol. 12, p. 4. 



Specimens. — Thirteen, from the following localities: 



Sudan: Kerma, 1 (Rothschild); Khartoum, 10, including 3 in 



alcohol (Heller, Loring); Merowe, 1 (Rothschild); Shereik 1 (Roths- 



chUd). 



ARVICANTHIS TESTICULARIS 3EBELJE HeUer. 



Plate 35. 



1911. Arvicanthis jehelx Heller, Smithsonian Misc. Coll., vol. 56, No. 17, p. 9. 



February 28. (Rhino Camp, Lado Enclave; type in U. S. Nat. Mus.) 

 1911. Arvicanthis testicularis jehelx Dollman, Ann. and Mag. Nat. Bist., eer. 8, 



vol. 8, p. 338. September. 



Specimens. — Thirty-three, from localities as follows.: 



Lado: Rhino Camp, 32, including 8 in alcohol (Loring, Mearns). 



Uganda: Gondokoro, 1 (Loring). 



The single specimen from Gondokoro is indistinguishable from the 

 lighter colored skins in the series collected west of the Nile. At both 

 Rhino Camp and Gondokoro distinct forms of the dark-bellied 

 Arvicanthis ahyssinicus group are also found. These latter are 

 sharply separated by the Nile and it would therefore not be surprising 

 if a better series from Gondokoro made it possible also to distinguish 

 a form of testicularis, separate from the Lado subspecies, on the east 

 side of the river. 



ARVICANTHIS AHYSSINICUS CENTROSUS Hollister. 



Plate 35. 



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



p. 10. February 28. (Part, specimens from Rhino Camp, Lado; not of 



Wroughton.) 

 1916. Arvicanthis abijssinicus centrosus Hollister, Smithsonian Misc. Coll., vol. 



66, No. 10, p. 1. October 26. (Rhino Camp, Lado; type in U. S. 



Nat. Mus.) 



Specimens. — Sixteen, including two in alcohol, from: 



Lado: Rhino Camp (Loring, Mearns). 



This subspecies of Arvicanthis ahyssinicus is readily distinguished 

 from Arvicanthis testicularis jehelse, Heller, which occupies the same 

 region in the Lado Enclave, by its much darker color, above and below, 



» See Thomas, Ann. and Mag. Nat. Hist., ser. 8, vol. 18, pp. 67-70. July, 1916. 



