EAST AFRICAN MAMMALS IN NATIONAL. MUSEUM. 71 



RATTUS KAISERI HELLERI Hollister. 



Plate 19. 



1914. Epimys kaiseri centralis Heller, Smithsonian Misc. Coll., vol. C3, No. 7, 

 p. 10. June 24. (Rhino Camp, Lado; type in U. S. Nat. Mus.) 



1918. Rattits helleri Hollister, Proc. Biol. Soc. Washington, vol. 31, p. 97. 

 June 29. (New name for Epimys kaiseri centralis Heller, 1914, preoccu- 

 pied by Mus auricornis centralis Schwann, Proc. Zool. Soc. London, 1906, 

 p. 107.) 



Specimens. — Forty-eiglit, from the type locality, as follows: 



Lado: Rhino Camp, 48, including 5 in alcohol and 2 odd skulls 

 (Loring, Heller, Mearns). 



This is a slightly characterized form of the Icaiseri group, in color 

 very much like Rattus Icaiseri norx, of northern British East Africa, 

 but averaging slightly smaller, with shorter hind foot and tail, and 

 lighter dentition. I have not seen specimens of Rattus Icaiseri Icaiseri 

 from Marungu. The specimens from Uganda, mentioned by HeUer 

 in the original description of ^' centralis^' as somewhat less typical in 

 character, I have placed with Rattus Jcaiseri medicatus, as they seem 

 to go best with specimens of that subspecies. The Nile is apparently 

 the dividing line between the two forms. 



For measurements of specimens of rats of the Rattus Icaiseri. group 

 see pages 73-75. 



• RATTUS KAISERI MEDICATUS (Wroughton). 



1909. Mus medicatus Wroughton, Ann. and Mag. Nat. Hist., ser. 8, vol. 4, p. ' 

 540. December. (Mumias, British East Africa; type in British 

 Museum.) 



1918. Rattus medicatus Hollister, Bull. 99, U. S. Nat. Mus., pt. 1, p. 178. 

 August 16. 



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



Uganda: Gondokoro, 3, including 1 in alcohol (Loring); Hoima, 

 2, including 1 in alcohol (Loring); Kabula Muliro, 4, including 2 

 in alcohol (Loring); Kikanda, 2, including 1 in alcohol (Loring); 

 Kisingo, 2, including 1 in alcohol (Loring); Lialo, 2, including 1 

 in alcohol (Loring) ; Lombeki River, 1 in alcohol (Loring) ; Nimulc, 

 2 (Loring); Nkyanuna, 2, including 1 in alcohol (Loring). 



British East Africa: Kaimosi, 2, including 1 in alcohol (Heller); 

 Kakumega, 1 (Heller) ; Lukosa River, 1 (Heller) ; Sirgoit Lake, Guas 

 Ngishu Plateau, 1 (HeUer). 



This long-tailed, grayish-buff subspecies of Icaiseri is very like both 

 helleri and norse in color, and the boundaries of distribution for the 

 three subspecies are difficult to define. The Nile appears to be a 

 convenient separating line between medicatus and Ticlleri, as the 

 greatest break in dimensions comes at that point. The Uganda 

 specimens listed above were all included by Heller with his "centralis," 

 but seem best placed with the earlier described medicatus. 



64952— 19— Bull. 90, pt 2 6 



