Stcamp-Rats of East Afrira. 



If 5 7 



of nnsaU IG'/i; wiiltli across expanded anterior portion iVH ; 

 depth froju lji<jlicst point of orbit to alveolar border at front 

 of m' 12-5 ; palatilar length 17 ; len;;tli of upper molar series 

 from front alveolar border to back of last molar *}''*. 



Hub. Mubukii Valley, lOast Kuwenzori. Altitude 12,500 

 feet. 



Tifpe. Adult male. B.M. no. (). 7. 1. <)4. 



Tliis species is easily distinguished trom the other members 

 of the division by its soft woolly pela<re and the presence of 

 only 6 lamina} in »i\ 



Group '2. 

 »j* with 7 lamina?. 



(10) ( Uomjjs ja chson j", T h 03 . 

 Olomyt jacktoni, Thos. Ann. & Mag-. Nat. Hist. (0) vol. vii. p. 2 (1891). 



Otomys jacksoni is distinguished from the other members 

 of the division by its small size ; the ])rescnce of 7 lamina; 

 in »i' readily separates the jacksoni group from dartnioutlii 

 with only 6 lainiuJB, and from the typus or 3rd group with 

 8 laminre in vi^. 



In size jacksoni is smaller tiian 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-butf, 

 the eflfect almost as dark as in /. nubilus described above. 

 Backs of hands and feet greyisii brown. 



Skull considerably smaller than in any of the other species 

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

 accentuated as in dartmoulhi and the following species, the 

 brain-case not being so depressed posteriorly. Molars rather 

 narrow, wi' with 7 laminae. 



Dimensions of the type : — 



Head and body 120 mm. ; hind foot 2Q. 



Skull : greatest length W'rl ; basilar length 28 ; zygo- 

 matic bri'adth 18*1 ; breadth of brain-case !.'>•.') ; 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 1')'5 ; length of upper molar series fium 

 iront alveolar border to back of wj' 92. 



JIab. Crater of Mt. Elgon. Altitude 13.200 feet. 



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



The small size and dark colour of this KIgon species readily 

 separate it from the other four members of Division (". 

 The Otomys obtained by Mr. K, Kenip on Mt. Elgon was u 



