12 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 56 



URANOMYS UGANDA, new species 



Uganda Big-toothed Mouse 



Type from Kikonda, Uganda; adult male, number 164822, U. S. 

 Nat. Mus. ; collected by J. Alden Loring, January 2, 1910; original 

 number, 8570. 



Specific characters. — Most closely related to rttddi of the Mount 

 Elgon District of British East Africa. Differs decidedly in the 

 shorter and narrower skull and the shorter nasal bones. Size 

 smaller and coloration of under parts without any pinkish wash. 



Coloration. — Median portion of head and body above sepia flecked 

 minutely with light brown, changing gradually on sides of head and 

 body to a fulvous flecked with sepia. Under parts light grayish^ 

 with a buffy wash. Fore and hind limbs with the color of the 

 sides, except the feet, which are white. Tail dusky brownish above, 

 becoming somewhat lighter below. 



Measurements. — Head and body, loi mm.; tail, 75; hind foot, 18; 

 ear, 12. Skull: greatest length, 27; condylo-basal length, 25; zygo- 

 matic breadth, 14.5 ; nasals, 7.5 x 3.5 ; upper toothrow, 4.5 ; palatal 

 foramina, 7.5. 



The skull of this genus is very close to Acomys in structure, the 

 palatal region especially being similar, but externally this species 

 can be scarcely distinguished from Lophnrornys aquilas, with which 

 it is found associated. The collection contains but a single speci- 

 men. The teeth in this individual are quite worn, so that the tuber- 

 cular structure cannot be made out. Compared with skulls of equal 

 age of Lophnrornys and Acomys, the m^ is found to lack the minute 

 posterior median cusp which is found in both these genera. The 

 structure of the floor of the skull closely resembles Acomys. The 

 depressions marking the termination of the bony palate are, how- 

 ever, much deeper and have prominent margins, the interpterygoid 

 fossa is wider and has parallel sides and blunt bead-shaped ptery- 

 goid processes. The mandible resembles more that of Lophnrornys 

 in the shape of its coronoid process, which is long and slender and 

 very different from the minute projection which is found in Acomys. 

 The condylar process is considerably larger than in either Lophn- 

 rornys or Acomys. The most marked difference, however, is the 

 prominence given to the incisor capsules. In this genus the capsule 

 forms a prominent shelf-like projection midway between the coro- 

 noid and the condylar processes. The incisor condyle of Acomys and 



