164 Miller A New Gerbille from Eastern Turkestan. 



colors, the ecru-drab especially noticeable on sides, cheeks and shoulders. 

 Ears and ill defined area immediately surrounding cadi dull white. A 

 whitish spot above and slightly behind eye. Underparts and entire 

 front leg white. On hind leg the color of back extends nearly to ankle. 

 Feet white, slightly gray-tinged. Fur of colored area of pelage gray 

 (Ridgway, No. 6) through a little more than basal half, that of un- 

 colored area white to base. Tail uniform pale buff throughout. 



Skull. The skull closely resembles that of Gerbillus przewalskii, but 

 the rostrum appears to be more slender (particularly when viewed 

 from below) and the braincase longer in proportion to its breadth. In 

 each of the three specimens of O. arenicolor the mastoid breadth is dis 

 tinctly less than the distance from posterior edge of interparietal to naso- 

 frontal suture, while in the paratype of G. przewalskii it is equal to this 

 distance. Mandible and teeth as in G. przewalxkii. 



Measurements. External measurements of type: total length, 162; 

 head and body, 89; tail vertebrte, 73; hind foot, 26.4 (24)'. 



Cranial measurements of type: greatest length, 27.4 (26)*; basal length, 

 24 (23); basilar length, 22 (21); nasals, 9 (8.6); diastema, 8 (7); zygomatic 

 breadth, 16 (15); least interorbital breadth, 6 (6); mastoid breadth, 15 

 (15); distance from posterior margin of interparietal to naso frontal 

 suture, 17.4 (15); mandible, 14.8 (14); maxillary toothrow (alveoli) 4 

 (4); mandibular toothrow (alveoli), 4 (4). 



*Measurements in parenthesis are those of the paratype of G. 



