Microtus mongolicus (Radde, 1861) . Melanges Biol. Acad. St. Petersb., 3:681.

TYPE LOCALITY: U.S. S. R., R.S.F.S. R., Chitinsk. Obi., Omutnaya River (tributary to Amur River) .

DISTRIBUTION: N.E. China (SW), N. Mongolia, and Transbaikalia (U.S. S.R.).

COMMENT: Subgenus Microtus (= Arvalomys Chaline, 1974); see Meier, 1978, Trudy Zool. Inst., Leningr., 75:3-62; regarded by Ellerman and Morrison-Scott, 1951:697, as a synonym of arvalis; separated by Malygin and Orlov, 1974, Zool. Zh., 53:616-622, and Malygin, 1978, Abstr. Pap., II Congr. Theriol. Internat. Brno, p. 331.