=_Clethrionomys gapperi galei_= (Merriam).--The 22 specimens (60005-60025, 70133) of Gapper's Red-backed Vole were taken at localities 6, 7, and 10, and are clearly referable to _C. g. galei_, rather than to _Clethrionomys gapperi gauti_ to the south, on the basis of generally dark dorsal pelage, indistinctly bordered broad dorsal stripe, and cranial features. _C. g. gauti_ was described by Cockrum and Fitch (1952, Univ. Kansas Publ., Mus. Nat. Hist., 5:289) on the basis of 14 specimens from southern Colorado and northern New Mexico. Twenty-one additional specimens from five miles south and one mile west of Cucharas Camps, Huerfano County, were obtained from the seventh to the fourteenth of July by the field party led by Tordoff after the party left the Grand Mesa. These specimens substantiate the subspecific distinctness of _C. g. gauti_ in that they agree in external and in cranial appearance with the description of typical _C. g. gauti_, and are distinct in appearance from specimens of _C. g. galei_ from the Grand Mesa and from other localities in northern Colorado. The six specimens from two localities in Colorado available to Cockrum and Fitch exhibited evidence of intergradation at one locality, and atypical smallness at the other locality. A specimen (70134) taken on June 26, 1956, by Phillip M. Youngman on the Black Mesa, nine miles WNW of Sapinero, 9500 ft., Gunnison County, Colorado, is almost identical in color to the two specimens from Saguache County regarded by Cockrum and Fitch as intergrades between _C. g. galei_ and _C. g. gauti_, but in small size of auditory bullae and narrowness of braincase resembles _C. g. galei_, to which it seems best referred. The specimens from the Grand Mesa extend the known range of _C. g. galei_ approximately 50 miles westward in central Colorado from Gothic. Three females were pregnant; two trapped on June 17 and June 25 contained 6 embryos each, and one trapped on June 25 contained 5 embryos. Four of the females taken in Huerfano County were pregnant; one contained 3 embryos, two contained 5 embryos, and one contained 7 embryos. Immature individuals are present in the sample from Huerfano County also. =_Phenacomys intermedius intermedius_= Merriam.--Three Heather Voles (60048, 60049, 70135) were trapped at localities 6, 7, and 10. All were adult females; one, taken on June 25 at locality 6, contained seven embryos five millimeters in length, and one, taken on July 2 at locality 7, contained seven embryos nine millimeters in length. These specimens extend the known range of the species approximately 55 miles west from Gothic (Pruitt, Jour. Mamm., 35:450, 1954). =_Microtus longicaudus mordax_= (Merriam).--Ten Long-tailed Voles (60070-60079) represent localities 3, 6, 12, 13, 14, and 15. =_Microtus montanus fusus_= Hall.--Ten Montane Voles (60060-60068, 70145) represent localities 3, 6, 7, and 15.