398 Mr. 0. Thomas on 



20. Evotomys r/lareolus saianicus, Tlios. 



cJ. 158; ?. 163, 172 (young). Syansk Mts., 100 miles 

 W. oCLfike Baikal. 1600'. 



Described Ann. & Mag. Nat. flist. (8) viii. p. 759 (1911). 

 No. 163 (B.M. no. 12. 4. 1. 85) the type. 



21. Evotomys riititus, Pall. 



cJ. 164. Syansk Mts., 100 miles VV. of Lake Baikal. 

 1600'. 



22. Arvicola terrestris, Linn. 



? . 159. Syansk Mts., 100 miles W. of L. Baikal. 1500'. 



23. Microtus cuconomus, Pall. 



S. 166, J 67, 168; ? . 169. Svansk Mts., 100 miles W. 

 of Lake Baikal. 2000'. 



24. Microtus arvalis, Pall. 



S . 273. 274, 276; ? . 265, 270, 272, 275. Barlik Mts. 

 S., N.W. Dzmigaiia. 5f)00-7O00'. 



? . 298 (young). Ala-tau Mts. S., N.W. Dzungaii;.. 

 2000'. 



? . 304. Tekes Valley, Thian Shan. 650'/. 



Judging by Biichnei-'s figure of the skull, M. eversmanni, 

 Pol., would seem to be cither this or a related form, and not 

 a Stenocranii's. 



Allied to M. arvalis, and from a locality quite close to the 

 present, is my recently described M. lUeus, easily distinguish- 

 able by its much larger skull. 



25. Microtus agrestis mongoJ^ Thos. 



S . 188. Kemichik Valley, Tannu-ola Mts., N.W. Mon- 

 golia. 4200'. B.M. no. 12. 4. 1. 102. Type. 



Described Ann. & Mag. Nat. Hist. (8) viii. p. 759 (1911). 



26. Microtus arcturuSj sp. n. 



? . 269. BarlikMts. S., N.W. Dzungaiia. 6000'. 17th 

 June, 1911. B.M. no. 12. 4. 1. 103. Type. 



A large brown vole like M. agrestis, but with additional 

 prisms on both ni^ and ni', as iu M. sikiment'is. 



Size rather exceeding that of the larger forms of .17. agresf/s, 



