A NEW RODENT OF THE GENCS SACCOSTOMUS FROM 

 BRITISH EAST AFRICA 



By GERRIT S. miller, Jr. 

 Curator, Division of Mammals, U. S. National Museum 



(With One Plate) 



A species of Saccostomus equally distinct from S. campestris 

 Peters and S. mcarnsi Heller^ is represented by three specimens col- 

 lected by J. Alden Loring, Field Naturalist of the Smithsonian 

 African Expedition, at Njori Osolali, British East Africa. It is 

 -described in this paper, the fifth dealing with the results of the 

 -expedition. 



SACCOSTOMUS UMBRIVENTER, sp. nov. 



Plate i, </, Skull, Natural Size 



Type. — Adult female (skin and skull), No. 162612. Collected at 

 Njori Osolali (Sotik), British East Africa, June 26, 1909, by J. 

 Alden Loring. Original number, 6447. 



Diagnosis. — Size and general external appearance as in Saccosto- 

 mus campestris and S. mcarnsi, but differing from the former in the 

 conspicuous plumbeous bases of hairs of underparts and from the 

 latter in the more bufity sufifusion of back and sides. Skull with pits 

 near posterior margin of palate minute as in S. campestris, but with 

 incisive foramina extending fully half way from maxillo-premaxil- 

 lary suture to incisors, as in S. mearnsi. 



Color. — Upperparts an indefinite light brown approaching the 

 wood-brown of Ridgway, lighter and more huffy on sides, darker on 

 back, along middle of which there is a faint clouding of much darker 

 brown ; a few longer black hairs on both back and sides, but these 

 not producing any evident effect of "lining" ; underparts sharply 

 defined white with a faint bufify tinge, the gray (about gray No. 6 

 of Ridgway) bases of the hairs everywhere appearing conspicuously 

 at surface; ear dusky with a narrow silvery rim; feet white; tail 

 too thinly haired to have any definite color, the hairs of under sur- 

 face w'hite, those of upper surface mixed black and white. 



' Smithsonian Miscellaneous Collections, vol. 54 No. 1924, P- 3- February 28, 

 1910. 



