352 Mr, G. Dollman on Arvicantliis abyssluicus 



Dimensions in millimetres (measured in the flesli) : — 



Average of 



8 adults. Max. Min. 



Head and body 127 134 120 



Tail 99 108 94 



Hind foot 24 25 23 



Adult skull (type) : greatest length 30'4 mm. ; basilar 

 length 26; condylo-incisive length 29*9 ; zygomatic breadth 

 16 ; squamosal breadth of cranium 12; interorbital constric- 

 tion 5 ; length of nasals 12'7 ; palatilar length 14*3; length 

 of palatal foramina 6*5 ; alveolar length of upper molar 

 series 6. 



Tj/pe locality. Shuk, Northern Somaliland. 



Type in British Museum, no. 97. 12. 3. 9. 



Since this species was described Dr. Drake-Brockman has 

 presented to the Museum a series of Arvicanthis from Upper 

 iSheikh, Somaliland, and these specimens, although rather 

 richer in colour than the type, apparently represent the true 

 somalicus. 



(IG) Arvicanthis reptans, DoUm. 



Arvicanthis reptans, Dollman, Ann. & Mag. Nat. Hist. (8) viii. p. 129 

 (1911). 



The smallest species of the ahi/ssini'cus group at present 

 known ; allied to somalicus. 



Size of body small, average length 114 mm. ; tail and hind 

 foot much as in somalicus. General colour above pinkish 

 brown speckled with black, the black tint most evident down 

 the middle of the back. Flanks rather more buff-coloured 

 than back, sharply marked off from tiie white ventral surface. 

 Hairs of back with black bases, buff-coloured subterminal 

 rings, and dark tips. Ocular rings, nose, and ears bright 

 orange-buff. Backs of hands and feet light buffy orange. 

 Under surface of body greyish white tinted with buff. Tail 

 as in somalicus, dark blackish brown above and light buff 

 below. 



Skull like that of somalicus, but smaller and less elongate. 

 Molar teeth rather small. 



Dimensions in millimetres (measured in the fle>h) : — 



Average of 



10 adults. Max. Min. 



Head and body 114 121 100 



Tail 97 111 87 



Hind foot 24 25 22-5 



