Sicamp-Rafs of East Africa. 167 



of nasals 16'5; widtli across expanded anterior portion &S ; 

 depth from highest point of orbit to alveolar border at front 

 of m^ 12'5 ; palafilar length 17 ; length of upper molar series 

 from front alveolar border to back of last molar 9*5. 



Hab. Mubuku Vallej, East Ruwenzori. Altitude 12,500 

 feet. 



T^pe. Adult male. B.M. no. 6. 7. 1. G4. 



Tiiis species is easily distinguished from tlie other members 

 of the division by its soft woolly pelage and tlie presence of 

 only 6 laminae in m^ 



Group 2. 

 »«' with 7 laminfe, 



(19) Otom^sjaclcsom'f Tho8. 

 Otomys jacTisoni, Thos. Ann. & Mag. Nat. Hist. (6) vol. vii. p. 2 (1891). 



Otomys jachsoni is distinguished from the other members 

 of the division by its small size ; the presence of 7 iaminsB 

 in m' readily separates the jacksoni group from dartinouthi 

 with only 6 laminae, and from t'le ti/pus or 3rd group with 

 8 laniinas in ni^. 



In size jacksoni is smaller than any other East African 

 Otomys ; both the skin and skull dimensions are remarkably 

 small. 



General colour a great deal darker than in the foregoing 

 species, back dark blackish brown mixed with orange-buff, 

 the effect almost as dark as in t. nuhilus described above. 

 Backs of hands and feet greyish brown. 



Skull considerably smaller than in any of the other species 

 treated of in this paper. The arched character is not so 

 accentuated as in dartniouthi and the following species, the 

 brain^case not being so depressed posteriorly. JMolars ratlier 

 narrow, m^ with 7 laminse. 



Dimensions of the type : — - 



Head and body 120 mm. ; hind foot 26. 



Skull : greatest length 35'7 ; basilar length 28 ; zygo- 

 matic breadth 18'1 ; breadth of brain^case 15*5 ; length of 

 nasals 16 ; width across anterior expansion 6'8 ; depth from 

 highest point of orbit to alveolar border at front of m^ 11*2 ; 

 palatilar length 15*5 ; length of upper molar series from 

 front alveolar border to back of ni^ 9'2. 



Hah. Crater of Mt. Elgon. Altitude 13,200 feet. 



Type. Adult female. B.M. no. 93. 2. 3. 34. 



Ttie small size and d^rk colour of this Elgon species readily 

 separate it from the other four members of Division 0. 

 The Otomys obtained by Mr. R, Kemp on Mt. Elgon was a 



