510 Mr. E. C. Wroughton on new 



O' 



Skull * : greatest lenoth 45 (42) ; basilar length 38 (34) ; 

 palatilar length 22*5 (20'3) ; greatest breadth 23 ; nasals 

 length ]9 (16) ; interorbital breadth 7*5 (7"4) ; brain-case 

 breadth IT'S (18*6) ; diastema 13*8 (12) ; upper molar 

 series 6"5 (6"8). 



Bab. Kiriii, Mt. Elgon. Altitude 6000'. 



Type. Old male. Rudd Collection. Original number 238. 

 Collected by 11. Kemp, 11th Sept., 1909. 



I have much pleasure in dedicating this species to Mr. 

 Dundas, who has quite recently presented to the Museum a 

 }Ounger specimen from Mumias (alt. 4500'), Judging from 

 this individual, the tail in this species (as in ruwtnzorii and 

 synithi) is practically untufted, and that of the type, whea 

 complete, was 180-190 mm. long. In my key to the genus 

 Tatera (Ann. & Mag. Nat. Hist., May 1906, p. 477) these 

 three species should stand together with nigrita in a group 

 separated from all the other species under II. A. by the 

 greater length of the posterior palatal foramina. Within this 

 group vigrita is isolated by its black colour and small size, 

 dundasi by its very large size, and ruice nzorii Vindi sviithi from 

 one another by the bright buffy colour of the one and the 

 duller greyish colour of the other. 



Mus medicatus, sp. n. 



A rat allied to and resembling 31. hindei from Machakos, 

 but somewhat smaller and wuth a much longer tail in propor- 

 tion to the body. 



Fur soft and silky, 12-15 mm. long on back. General 

 colour duller than in hindei, ground-colour near "salmon-buff," 

 much mixed with black on back, less so on sides, passing 

 rather abruptly but without any definite line into white of 

 belly, this last looking almost grey owing to the long slaty 

 bases of individual hairs. Hands and feet white. Tail 

 unicolorous, very sparsely haired, dark. 



Skull as in hindei, but larger, the bullae larger and the 

 palatal foramina longer. 



Dimensions of the type : — 



Head and body 160 mm. ; tail 178; hind foot 30 ; ear 21. 



Skull: greatest length 40; basilar length 33 ; zygomatic 

 breadth 20; nasals 15; interorbital breadth 6; brain-case 

 breadth 155 ; diastema 10*5 ; upper molar series 6'2. 



Bab. Mumias, B. E. Africa. Alt. 4500'. 



* The figures in brackets are those of Tntera smithi. 



