344 Jlr. G. Dollman on Arvicantliis abysslnicus 



buff; hairs of belly and throat with slaty-black bases and 

 buffy-white tips. Tail short, rather less hairy than in 

 ahi/ssinicus ; above dark blackish brown, below dark grey- 

 coloured. 



Skull a trifle smaller than in Ruppell's species, nasals 

 rather short. 



Dimensions of the type (measured in the flesh) : — 

 Head and body 136 mm.; tail 112; hind foot 28-5; 

 ear 16. 



Skull : greatest length 32-5 ; basilar length 27*3 ; condylo- 

 incisive length 31"5; zygomatic breadth 17; interorbital 

 constriction 4'7 ; squamosal breadth of cranium 13"5; length 

 of nasals 11 ; palatilar length 15 ; length of palatal foramina 7 ; 

 alveolar length of upper molar series 7. 



Hah. Didessa River, near Guma, Abyssinia. 

 T^pe. Adult femalp. B.M. no. 6. 11. 1. 70, Original 

 number 83. Collected on June 5th, 1905, by Ph. Zapiiiro, 

 and presented to the British Museum by W. N. McMillan, 

 Esq. 



The very much darker and blacker colour of this Arvt- 

 canthis at once distinguishes it from the greyish olive-coloured 

 ahyssinicus. It is interesting to note that the young specimens 

 of this new form are quite as dark as the adults, and thus the 

 difference between the young of the two forms is most 

 striking, the young pelage of (7Z'^5.si/jrc(/5 being a great deal 

 paler than in the adult phase. In addition to the type, this 

 new race is represented in the Museum collection by three 

 further specimens, all collected near the type locality, in the 

 Guma district. 



(8) Arvicanthis aht/ssin/'ciis ruhescens, Wrought. 



Arvicanthis a. rubescens, Wrought. Ann. & Mag. Nat. Hist. (8) iv. 

 p. 638 <1909). 



Very similar in size to ahi/ssmicus, hind foot rather larger, 

 colour darker and redder, dorsal stripe less distinct. 



Size of body rather larger than that of obi/ssinicus (sLyernge 

 length 158 mm.) ; hind foot large (30 ram.) ; tail short. 

 General colour darker and more ocliraceous than in ahi/ssini- 

 cus, the whole dorsal surface washed with a rich buft-coloured 

 tint. Ko light areas behind ears. Face like tlicitof ah t/ssini- 

 cuSy rather richer in colour. Dorsal stripe indistinct, in some 

 cases almost invisible. Backs of hands and feet buff-co!ourcd. 

 Under surface rather lighter than in aht/ssi'uicus. Tail less 

 Lairy, but very similar in colour. 



