546 MR. o. THOMAS ON THE [May 3, 



position. The type, and only known specimen, was obtained at 

 Tankse, Pankong Lake, Ladak, at a height of 13,000 feet. 



12. MUS BACTRIANUS. 



*J/. bactrianus, Blyth, J. A. S.B. xv. p. 140 (1846); Blanfoid, 

 Zool. East Pers. i. p. 56, pi. v. fig. 2 (1876) ; Danf. & Alst. P. Z. S. 

 1880, p. 61. 



M. gerbillinus, Blyth, J. A, S. B. xxii. p. 410 (1853) ; Cat Mus. 

 As. Soc. p. 119 (1863). 



M. theobaldi, Blyth, J. A. S. B. xxii. p. 583 (1853). 



Hab. N.W. India and Cashmere, and westwards to the Euphrates 

 {Banford and Alston) ; Palestine {Brit. Mus., Tristram) ; Muscat, 

 Arabia {Blanford). 



Fur rather short and crisp ; above sandy fawn, the bases of the 

 hairs slate-colour ; below usually pure white, but with sometimes a 

 slight basal tinge of slate, especially in immature specimens. Ears 

 rather shorter than in M. nrbanus, covered inside and out with 

 sandy-brown hairs. Tail about the length of the head and body, or 

 as a rule rather longer, brown above and white beneath, the dif- 

 ference, however, not being strongly marked. Ceecum simple, about 

 0'7 inch long. Mammee 10, three pectoral and two inguinal pairs. 



The type has a more reddish coloration than usual on the upper 

 side ; but otherwise it is similar to Persian and Syrian specimens. 



The skull presents no characters worthy of remark, being almost 

 exactly like that of 3Ius musculus. In immature specimens it is much 

 more convex above than it is later, and the nasal region is shorter. 



Dimensions. 



BaluchiBtan. 

 a. d- 



Head and body 3"4' 



Tail 3-55 



Hind foot 75 



Tibia' -92 



Forearm and hand "90 



Ear-conch, length '47 



Muzzle to ear 



This species is always readily distinguishable from other Indian 

 Mice by its pale colour and white belly. It would appear to be a 

 true desert form, having the coloration peculiar to the inhabitants 

 of sandy plains and being found only in districts where such plains 

 form a large part of the country, 



Messrs. Danford and Alston (/. c.) give the dimensions of two 

 spirit-specimens taken at Oroul on the Euphrates ; but I should 

 imagine that there has been some misprint among the figures, as I 



^ Skull extracted. 



^ From the upper side of the knee-joint to the sole, 



