152 ]\Ir. G. Dollman on the 



Division A. 



Lower iucisors witb ouly one very deep groove. General colour very 

 dark ; ventral surlace ot tail dull black. 



Group 1. 

 7h' with 5 lamiufe. 



(1) Otomys denti, Thos. 



Otomys denti, Tbos. Ann. & Mag. Nat. Ilist. (7) vol. xviii. p. 142 

 (190G). 



Lower incisors with only one deep groove, large inner 

 portions terminating in two sharp points, sharper and longer 

 than in the other groups ; small outer portions sharply pointed 

 and usually very pale in colour, a feature so marked that the 

 skulls of this group cau be immediately recognized. Brain- 

 case flat. 



In colour this species is exceedingly dark, the dorsal sur- 

 face being brownish black (*' blackish brown (3) " s])ecklod 

 with "auburn," Ridgway, 1012) speckled with coppery buff. 

 Backs of hands and teet blackisli brown. Ventral surface of 

 body slate-black slightly speckled with buff. Tail dull black 

 above and below. With the exception of the following 

 species, all the other East-African Otomys have a light 

 under surface to the tail. 



Dimensions of the type : — 



Head and body 157 mm. ; tail 89; hind foot 27 ; ear 21. 



Skull: greatest length 36*7; basilar length 30"2; zygo- 

 matic breadth 18'3 ; breadth of brain-case 15"5 ; length of 

 nasals 1'4"7 ; breadth of anterior expanded portion 7 ; pala- 

 tilar length 1G"8 ; length of upjier molar series from front 

 alveolar border to back of last molar 8'3. 



The molars are rather small, vi^ possessing only 5 laminee. 



Jlah. Ruwenzori East. Altitude 6000 feet. 



Type. Old female. B.M. no. 6. 7. 1. 69. 



Externally denti and the following 3j)ecies are immediately 

 recognized by their very dark colour and the dark ventral 

 surface of the tail. 



Group 2. 

 m' with 6 laminae. 



(2) Otomys kempi, sp. n. 



Allied to 0. dend, Thoa., but distinguished by 7u^ possessing 

 6 instead of 5 laminse. 



In general dimensions a trifle larger than the Ruwenzori 

 Bpecies. The description given above for the colour of denti 



