A new Jerboa from China. 307 



XXXIV. — A new Jerboa from China. 

 By Oldfielu Thomas. 



Hitherto the only Jerboa known from China has been the 

 rive-toed AUaclaga mongolica, Radde (A. annulata, M.-Ed\v.), 

 and it has therefore been with much interest that I have 

 examined a three-toed species from Shensi, recently pre- 

 sented to the National Museum by Mr. A. de C. Sowerby. 

 It proves to be a distinct form allied to Dipus sagitta, Pall., 

 and may be characterized as follows : — 



Dipus sowerbyi, sp. n. 



Size considerably greater than in D. sagitta and its close 

 ally D. deasyi, B. Ham. General colour sandy buff varying 

 towards fawn, more or less darkened along the dorsal area. 

 White lines on rump well defined, prominent. Head and 

 ears like body. Outer side of legs, from knees to ankles, 

 rich buffy, contrasting markedly with the pure white of 

 their inner surfaces. Fore limbs, whole of under surface, and 

 hind feet pure white, the long hairs under the toes slightly 

 suffused with buffy ; a narrow line under heel blackish. 

 Tail buffy or pale fawn above, white below ; the terminal 

 half-inch white, the blackish band preceding it about three 

 quarters of an inch in length. 



Skull comparatively stout and heavy, its muzzle parti- 

 cularly broad, broader in proportion to the brain-case than in 

 the other species- Thus the breadth of the muzzle halfway 

 along the nasals is quite half the least interorbital breadth, 

 considerably less than half in D. deasyi and sagitta. Bullae 

 larger than in I). deasyi, but of course not approaching their 

 development in the genus Jaculus. 



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



Head and body 116 mm.; tail 169; hind foot 65; ear 22. 



Skull: greatest length 34*5; basilar length 25*8 ; greatest 

 breadth 22 ; nasals 12*5 ; breadth of muzzle 5*2 ; inter- 

 orbital breadth 10 ; breadth of brain-case 18'3 ; palatilar 

 length 16 - 7 ; palatal foramina 5*7 X 3 ; length of upper tooth- 

 row (molars only) 5'5. 



Hah. Yu-lin-fu, Shensi, China. Alt. 4000'. 



Type. Adult male. B.M. no. 8. 7. 31. 2. Original number 

 1790. Collected 29 April, 1908, and presented by Mr. 

 Arthur de C. Sowerby. Two specimens. 



Of the two specimens, both taken the same day, the 

 younger, curiously enough, is much the brighter of the two, 

 being nearly as bright a buffy as D. sagitta, while the older 

 specimen (the type) is more drabby in tone. 



