Voles from Yunnan. 149 



hand, with four salient angles on each side, is quite unre- 

 duced. E. prudifor, described below from the Lichiang 

 Range, is still less primitive, since cusp n is practically absent 

 from both m} and m^ (fig. 5), being represented in the latter 

 tooth merely by an obscure vestige. In this species (and 

 occasionally in E. olitor, cf. fig. 4) m"^ is of peculiar form, 

 the first outer infold being shallow, so as to leave the 

 anterior loop half confluent with the first outer triangle, as 

 in some species as Aiitelioniys^ Alticola, and certain other 

 voles. The following is a key to the various species and 

 subspecies : — 



A. Anterior upper cheek-teetli complex ; vi^ 



with four, nr with three salient aug-les on 

 the inner side. 

 a. vi^ with four inner angles. 



«\ /u^ with four outer angles ; bulIoD small, 

 teeth heavy. Colour bright. [Kachiu 



Prov., W. i3urma.] B. in. cachinus, Thos. 



6^ 7)1^ with three outer angles. 



d^. Size normal: condylo-basal length to 

 26 ; hind foot to 19 mm. 

 a^. Bulh^ large, teeth light. 



a'-. Colour dark. [Yunnan.] .... E. m. eJeusis, Thos. 

 6'. Colour bright. [Hupeh.] .... E. m. aurora, Allen. 

 h^. Bullae small, teeth heavy. 



a^. Skull strongly bowed dorsally. 

 Colour rather brighter. [W. of 



Yung-pi, Y^uunau.] E. m. miletus, Thos. • 



b^. Skull normal, not bowed dor- 

 sally. Colour rather darker. [Kiu- 



chiang-Salweeu divide.] E. m. confmii, sul)sp. n. 



h-. Size large : condylo-basal length 28, 

 hind foot 20 mm. Colour bright. [Li- 



chiang Range.] E. Jidelis, sp. n. 



h. ))i^ with three inner and three outer salient 

 angles. 

 a'^. JsulljB large, teeth light, 

 a^. Colour dark, buUre rather larger. 



(Mou])in, W. Sze-chwan.] E. m. melanof/aster. 



//-. Colour btiglit, buUaB rather smaller. 



[N.W. Fokien.] E. 771. colarntis, Thos. 



h\ BnllfB small, teeth heavy. Colour verv 

 d:.rk. 

 «-. Larger (hind foot 19 mm), witli [Allen. 



broad brain-case. [W, Sze-chwan.] . E. 7n. mucro7iatus, 

 b^. Smaller (hind foot 17 mm.), with 



narrow brain-case. [Mishmi Hills.] . E.m.libonotus,suhi^.n, 



B. Anterior upper cheek-teeth more or less 



simplified, 771^ wath only three inner angles. 



a. Small (condylo-basal length to 24 mm.) ; 



?;r normal, with three inner angles ; wi' 



complex, w^ith four inner and four outer 



salient angles. [Chao-tung-fu, Yunnan.] E. olitor, Th.)s. 



