338 Mr. G. Dollman on Arvicanthis abyssinicus 



impossible to decide the affinities o£ this form. The type 

 locaUty, Syrkut, Upper Nubia, is so situated that minor 

 mio-ht represent a geographical race of either testicular is or 

 niloticus. 



(2) Arvicanthis tesdcularis jehelm, Hell. 



Arvicanthis jebelce, Heller, Smith, Miscall. Coll. vol. Ivi. (17) p. 9 

 (1911). 



A form closely related to testicularis, differing only in its 

 rather smaller size and more olive coloration. 



The general colour of the dorsal surface rather less sandy 

 than in testicularis ; the colour scheme more like that of the 

 true abyssinicus, but retaining the ochraceous colouring of 

 testicularis. Nasal region not so buffy, the hairs rather 

 darker and browner. Ears rather darker in colour. Under 

 surface, feet, and tail as in testicularis. 



Skull smaller than that of testicularis, with much shorter 

 palatal foramina. Molar teeth markedly smaller. 



Dimensions of type (measured in the flesh) : — 



Head and body 140 ram.; tail 150; hind foot 29. 



Skull : greatest length 35'5 ; condylo-incisive length 31"5 ; 

 zygomatic breadth 17 ; interorbital constriction 5 ; length of 

 palatal foramina 5*5 ; length of upper tooth-row 6*5. 



Type locality. Lado Enclave. 



In the British Museum are three specimens from the Kit 

 River, Bahr-el-Gebel, which appear to represent this Lado 

 form of testicularis, and it is evident from examination of 

 these specimens and the original description that the Lado 

 Arvicanthis must be regarded as a geographical race of 

 testicularis, and not, as suggested by Heller, as a distinct 

 species allied to A. abyssinicus rubescens, Wrought. The 

 exceptional length of tail, ochraceous colouring, and white 

 underparts are all characters diagnostic of testicularis. 



(3) Arvicanthis testicularis centralis, subsp. n. 



Allied to Arvicanthis testicularis, Suiid., ochraceous brown 

 in colour, without dorsal stripe, and having the white under- 

 parts sharply marked off from the buff-coloured flanks. 



In size and general proportions rather less than in testicu- 

 laris ; tail rather shorter, about equal to length of body. 

 General colour richer and darker ; dorsal surface ochraceous 

 buff lined with black. Hind-quarters and rump tinged with 

 reddish. No trace of dark dorsal stripe. Flanks paler and 

 purer in colour than back, the general effect rather yellower, 

 owing to the dark ground-colour being less in evidence. 



