new Mammals from East Africa. 657 



Head and face-markings much less evident than in nuhilus, 

 dark stripe on forehead and muzzle scarcely defined ; ocular 

 rings and dark area behind eyes almost invisible. Outer 

 surface of ears clothed with orange-buff hairs. Backs of 

 hands and feet and ventral surface of body white. Tail as 

 in nuhilus. 



Skull quite as in nuhilus, molar teeth a trifle smaller. 



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



Head and body 108 mm. ; tail 158 ; hind foot 29 ; 

 ear 19. 



Skull : greatest length 35 ; basal length 28 ; condylo- 

 incisive length 30 ; zygomatic breadth 18 ; interorbital 

 constriction 7 ; squamosal breadth of brain-case 15*3 ; length 

 of nasals 14; palatal length 17; length of palatal foramina 

 5*8; length of upper cheek-teeth 4'6; alveolar length of 

 upper cheek-teeth b'2. 



Hah. 12 miles north of the Eusso Nyiro. Altitude 

 3300 feet. 



Type. Adult male. Original number 326. Collected on 

 February 2nd, 1911. 



Thamnomys surdaster lutosus, subsp. n. 



c? . 397, 401, 403, 404 ; ? . 398, 399, 400, 402, 439. 

 Mt. Nyiro. Altitude 8000 feet. 



About equal in size to T. surdaster ibeanuSj Osg., but 

 much paler in colour. 



Size of body and hind feet as in i&eanu^, tail rather longer. 

 General colour very much that of T. s. polionops, Osg., but 

 less rufous on dorsal surface and without dusky markings on 

 sides of face. Colour of back paler and less buffy than in 

 T. s. insignis, the rufous tint only asserting itself on the hind- 

 quarters and rump. Flanks pale slate-grey tinted with 

 yellowish buff, a good deal paler than in either insignis or 

 ibeanus. Face and head gvey, tinted with pale yellowish 

 buff. In the coloration of the flanks and head this form 

 most nearly Yesemh\es polionops. Underparts creamy white, 

 liairs white to roots. Backs of hands and feet yellowish 

 white. Tail long, in colour and distribution of hair about 

 as in the allied races. 



Skull a trifle shorter and stouter than in either ibeanus or 

 insignis. 



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



Head and body 118 mm.; tail 198; hind foot 24; 

 ear 22. 



Skull : greatest length 31*4 ; basilar length 24*5 ; con- 



