referred to the Genus Merioncs. 271 



liackwards as tlie occipital, and their postmcatal portion is 

 l)iit little swollen, with a straight posterior margin. 



Dimensions of the type: — 



Head and body IGl mm. ; tail 183; liiad foot 41 ; 

 ear 28. 



Skull : greatest length (median) 43 ; condylo-incisivo 

 leiifTth 38*5 ; zygomatic breadth 22"5; nasals 16'6 ; inter- 

 orbital breadth 7 ; least breadth across brain-case 17*2 ; 

 meatal breadth 21*3 ; palatine foramina 8"3 ; u|)per molar 

 series 6"2. Bullre : greatest diagonal horizontal diameter 13 ; 

 distance from back of bulla to front of meatus 9 ; supra- 

 nieatal tri.inoflo, lenorth 3*5, liei;rht 2. 



Hah. (of typo). Dopnlan, Bmhfiari Mountains, 120 miles 

 N.R. of Alnvaz, Persia. Alt. COOO'. 



Type. Adult male. B.M. )io. 5. 10. 4. 35. Original 

 nuni'her 36. Collected 18th April, 1905, by K. B. Woosnam ; 

 presented by Col. A. C. Baihvard. 



In my account of the Baihvard collection * 1 referred this 

 exceedingly handsome gerbil to Al. persicus ; but now that I 

 realize the systematic value of the difference in size of the 

 bullae, I consider it should be distinguished specifically from 

 that animal. 



Meriones isis, sp. n. 



The Lower Egypt representative of the c group, that of 

 which M. sliaivi is typical. 



Size rather less than in true shawi. General colour rather 

 gieyish or drabby buff, but of the only two available skins 

 one has been exhibited for many years and the other skintied 

 out of spirit. Underside white, the hairs slaty at base. 

 Light ear-patches little developed. Tail rather shorter than 

 head and body, dull whitish or buffy whitish on the sides and 

 for its whole length below, slightly darkened above by 

 blackish hairs, but very little tufted at the end, the longest 

 hairs barely 10 mm. in length. 



Skull, as compared with that of M. gwjoni, the South- 

 Algerian and Trij)olitan representative of il7. s//a^^^, of similar 

 general form, with comparatively small bullae and small 

 sui)rainoatal triangles. Bullre, however, slightly smaller, and 

 interorbital breadth distinctly greater, this latter being the 

 chief difference between the Egyptian and Algerian animals. 

 Palatine foramina reaching to the level of the anterior root 



of 111}. 



* P. Z. S. 190o, ii. p. 5i>3. 



