Mammals from the Bahr-el-Ghazal. 503 



Five specimens examined. 



I liave named this species after ]\Ir. Gilbert Blaine, who 

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

 collection was made. 



14. Mus Butleri^ 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 silkj ; G-8 mm. long on the back. 



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

 colour from their bases for two thirds their length, 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 the neck and body fawn ; line between upper and 

 belly colours sharply defined ; feet white ; tail sparsely 

 liaired, daiker above than below, about 7-8 rings = 5 mm. 



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



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 4; brain- 

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

 bullae 5. 



Ilah. 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 jjre.sent form is se|iarable 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. Dennia;^ Thos., from Kuwenzori; but in that 

 animal the tail is ])roportionally still longer and the slaty 

 bases of the hairs of its underside distinguish it markedly 

 Ironi M. Butleri. 



15. Arvicanthis zebra, Ileugl. 



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

 'I'opotypes of lleuglin's species. 



