=Spermophilus franklinii= (Sabine). FRANKLIN GROUND SQUIRREL.--A specimen from 2 mi. NW of Lisco, in Morrill County (NSM 3324), extends the known geographic range of _S. franklinii_ approximately 200 miles westward along the Platte River Valley from Kearney, Buffalo County (see Howell, 1938:134), and suggests a westward movement of this ground squirrel along the Platte River in recent years. =Perognathus flavescens flavescens= Merriam. PLAINS POCKET MOUSE.--_P. f. flavescens_ occurs in the Sand Hills and adjacent mixed-grass plains of central Nebraska. Eastern marginal records of occurrence are: Neligh, Antelope County, 2 (MVZ 1, NSM 1); 1 mi. E of Ravenna, Buffalo County, 2 (MZ); unspecified locality in Adams County, 1 (HM). =Perognathus flavescens perniger= Osgood. PLAINS POCKET MOUSE.--This mouse occurs in northeastern Nebraska. Osgood (1904:127), in the original description of the subspecies, listed two specimens from Verdigris [Verdigre], Knox County. Additional records of occurrence are: Beemer, Cuming County, 2 (USBS); 1-1/2 mi. SE of Niobrara, Knox County, 3; 1-1/2 mi. S of Pilger, Stanton County, 2. The two specimens from Beemer are typical _perniger_. All of the other Nebraskan specimens are intergrades between _P. f. flavescens_, geographically adjacent to the west, and _P. f. perniger_ to the east but are best referred to _perniger_ on the basis of greater total length, larger cranial measurements and darker dorsal coloration. _P. f. perniger_ was originally described (Osgood, _op. cit._) on the basis of its darker dorsal coloration and encroachment of the lateral line on the posterior parts of the venter. The latter character is not present in all Nebraskan specimens. Mice from the two localities in Knox County have buffy underparts; those from other Nebraskan localities do not. Of nine specimens of _P. f. perniger_ examined from Elk River, Sherburne County, Minnesota, none has buffy underparts whereas a specimen from Randolph, Fremont County, Iowa (NSM) does. In addition, in two of five specimens of _P. f. flavescens_ from Kelso, Hooker County, (MZ) the lateral line encroaches on the underparts. The encroachment of the lateral line on the underparts, or failure of the line to do so, is thought to be only an individual variation and of no taxonomic use.