Mr. O. Thomas on Three new African Muridge. 181 



Mus Daltonij sp. n. 



Size medium. Fur fairly long, rather coarse. General 

 colour dull fulvous, not unlike tliat of many species of Ger- 

 hillus ; darker along the centre of the back, clearer fawn along 

 the sides. Chin, chest, and belly pure white, the hairs white 

 to their roots. Ears large, rounded, thinly clothed with minute 

 brownish hairs. Outer sides of limbs and wrists and ankles 

 coloured like the back ; inner sides and upper surfaces of 

 hands and feet white. Pads large and rounded, those of the 

 hind foot almost touching each other ; distance from the front 

 of the last hind pad to the heel equal to that from the same 

 point to the tip of the second toe ; the pad itself oval, but 

 little longer than broad ; hallux not reaching to the base of 

 the second toe ; fifth toe just to the end of the first phalanx of 

 the fourth. 



Tail about as long as the head and body combined, slender, 

 finely scaled, greyish above, rather paler below, thinly covered 

 with minute hairs, brown above and white below, which 

 slightly increase in length at the tip. Mammai 3 — 2=10. 



Skull with a narrow delicate muzzle ; interorbital region 

 flat, its edges square and slightly thickened, but without 

 raised ridges ; plate of anterior zygoma-root evenly convex 

 forward ; palatine foramina ending level with the anterior 

 laminge of 5iil; bullae rather small. Molars small and narrow. 



Dimensions of the type (B. M. 65. 3. 30. 6), a female 

 specimen preserved as a skin : — 



Head and body 117 milliin. ; tail 114; hind foot 19"2 ; 

 heel to front of last foot-pad 9' 1 ; ear 15. 



Skull : tip of nasals to lambda 23*3 ; greatest breadth 13"6 ; 

 nasals, length 11*6, greatest breadth 3'2 ; distance between 

 outer corners of infraorbital foramina 7'0 ; interorbital breadth 

 4*2 ; length of anterior zygoma-root 3"3 ; palate length 14*1, 

 breadth outside '^ 5'8, inside ^li 3*4 ; diastema 8*0 ; ante- 

 rior palatine foramina 6*4 ; length of upper molar series 4'2. 



Hah. W. Africa (probably Fernando Po). Collected by 

 Mr. J. T. Dalton. 



This species belongs to the group characterized by the 

 possession of 3 — 2= 10 mammai and by their otherwise general 

 resemblance to the multimammate African species. To this 

 group should be referred M. alhipes^ Hiipp., M. colonus^ 

 Brants, and M. anc/olensisj Boc. ; but all these are decidedly 

 larger than M. Daltoni and all have grey-based instead of 

 pure white belly-hairs. 



A second specimen obtained from Mr. Dalton at the same 

 time as the type agrees with it in every respect. 



