Mammals from the Bahr-el-Ohazal. 503 



Five specimens examined. 



I have named this species after Mr. Gilbert Blaine, who 

 was Mr. Butler's companion on the tour during which the 

 collection was made. 



14. AIus Butlerij sp. n. 



$ . 37. Between Chak Chak and Dem Zubeir. 8, iii. 07. 



A mouse rather smaller than the last, with a longer tail 

 and pure white belly. 



Size rather smaller than M. Blainei. 



Fur soft and silky ; 6-8 mm. long on the back. 



General colour above " clay-colour," the hairs slate- 

 colour from their bases for two thirds their lengtli, terminal 

 third a bright fawn, with short black tips; underside pure 

 white, the hairs white to their bases ; face below the eyes and 

 sides of tiie neck and body fawn ; line between upper and 

 belly colours sharply defined; feet white; tail sparsely 

 Laired, darker above than below, about 7-8 rings = 5 mm. 



Skull and teeth of the type normal in the genus Mas. 



Dimensions of the type : — 



Head and body 90 mm. ; tail 118; hind foot 20 ; ear 16. 



Skull: greatest length 27; basilar length 21; greatest 

 breadth 13; nasals 10; interorbital breadth 1; brain- 

 case breadth 12 ; diastema 7 ; length of upper molar series 4'5 ; 

 bullaB 5. 



Hah. Between Chak Chak and Dem Zubeir, Bahr-el- 

 Ghazal. 



Type. Young female. Collector's number 37. Taken 

 8th March, 1907. 



Though the size and proportions of the skull are so similar 

 in the two species, the present form is separable at once from 

 the last by its proportionally much longer tail and snow-white 

 belly. The species most closely resembling this one is 

 ])erhaps M. Dennice, Thos., from Euwenzori; but in that 

 animal the tail is proportionally still longer and the slaty 

 bases of the hairs of its underside distinguish it markedly 

 from M. Butleri. 



15. ArvicantJiis zebra, ITeuo-1. 



(?.48, 49. Dad Majok. 30. iii. 07. 

 Topotypes of Heuglin's f^pecies. 



