avd allic'l East-African Species. 351 



greyish, faintly tinted with pale buff. Under siiifaceof body 

 w hitisli ; hairs witii grey bases and white tips. Tail short, 

 coloured much as in praceps ; ventral surface less buffy. 



ISkull ijuiall, in size hardly larger than that of somalicus. 

 ^lohir teeth much smaller tiian in the allied species. 



Dimensions in n)illimetrcs (measured in the flesh) : — 



Averaj^'o of 



10 adults. Max. Min. 



Head and bodv 132 140 128 



Tail '. 95 107 88 



Hiiidfoot 25-8 27 23 



Adult tkull (type) : greatest length SI'S mm.; basilar length 

 2&\; condylo-incisive length 30; zygomatic breadth IG; inter- 

 orbital constriction 4 3 ; squamosal breadth of cranium 132; 

 length of nasals 12; palatilar length 14-3; length of palatal 

 foramina 7; alveolar length of u|)per molar series 5*9. 



Ti/pe locality. Kumruti, Laikipia Plateau, British East 

 Africa. 



Type in Britisli Museum. Original number 1413. Col- 

 lected by Ml-. Kobin Kemp on October 2Jth, 1910. 



The type locality is at present the only district in which 

 this species has been found. It does not appear to occur 

 either at Baringo on the west side or in the Eusso Nyiro 

 district to the east of Kumruti, since Mr. Kemp found only 

 A. jiraceps at Baringo and chanleri and reptans in the Eusso 

 Kyiro district. Probably this small Kumruti species is con- 

 fined to the high altitudes of the Laikipia Plateau. 



(15) Arvicanthi's somalicus, Thos. 

 Arvicanthis somalicus, Thomas, P. Z. S. 1902, ii. p. 312. 



In size about equal to rumrutl ; general colour sandy buff, 

 mixed with brownish black. 



8ize of body and tail about as in the foregoing species ; 

 hind foot rather smaller, average length 24 mm. General 

 colour pale sandy buff, lined with black and pale brown, 

 Flaidis paler and yellower than back. Nose, ocular rings, 

 and ears orange-buff. Backs of hands and feet buffy white. 

 Ventral surface of body white, hairs with grey bases and 

 white tips. Flanks fairly distinctly marked off from belly, 

 though this character is not evident in the type, which 

 appears to be rather a bleached specimen. Tail short and 

 similar in colour to that of the llumruti species. 



Skull small, rather less than in rumruti. Brain-case and 

 audiiory bullje much smaller than in the ahyssinicus group. 



