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.
Perognathus flavus piperi Goldman. Buffy Pocket Mouse.—In the description of P. f. bunkeri, Cockrum (1951:206) allocated to the new subspecies, without comment, a specimen from Alliance, Box Butte County. I have examined this specimen along with all other Nebraskan specimens known to me and, although all approach bunkeri in cranial measurements, they seem best referred to piperi on the basis of darker dorsal coloration and larger external measurements. Additional records of occurrence, several of them marginal to the eastward, are: 10 mi. S of Antioch, Garden County, 1 (MZ); Kelso, Hooker County, 4 (MZ); 5 mi. N of Bridgeport, Morrill County, 1 (MVZ); 6 mi. N of Mitchell, Scotts Bluff County, 1 (NSM). A specimen not seen by me that was reported from Valentine, Cherry County (Beed, 1936:21), is presumably also best referred to P. f. piperi.
No specimens of P. flavus are known to me from south of the Platte River in southwestern Nebraska although they probably occur there. If so, they may be referable to P. f. bunkeri, which is found in counties of Kansas adjoining the southwestern part of Nebraska.
Perognathus hispidus paradoxus Merriam. Hispid Pocket Mouse.—This subspecies occurs commonly in central-and western-Nebraska. Eastern marginal records of occurrence are: 2 mi. SE of Niobrara, Knox County, 1 (NGFPC); 4 mi. E, 2 mi. S of Ord, 1; Bladen, Webster County, 2 (HM).
Perognathus hispidus spilotus Merriam. Hispid Pocket Mouse.—Jones and Webb (1949:312) first reported this subspecies in Nebraska as from 5 mi. SE of Rulo, Richardson County. Additional records of occurrence are: 3 mi. SW of Barnston, Gage County, 1 (NGFPC); Bennet, 1 (NSM), 9 mi. NW of Lincoln, 1 (NSM), 1-1/2 mi. S of Lincoln, 1 (NSM), Lancaster County; Peru, Nemaha County, 1 (NGFPC); 3 mi. S, 2 mi. E of Nebraska City, Otoe County, 3; Barada, Richardson County, 1 (NSM); Pleasant Dale, Seward County, 1 (NSM); 1 mi. S of Williams, Thayer County, 1.
Glass (1947:179) referred a specimen from 9 mi. NW of Lincoln, Lancaster County, to P. h. paradoxus. In discussing the zone of intergradation between spilotus and paradoxus, geographically adjacent to the west, he wrote (op. cit.:178), "It is evident that it proceeds northeastwards, toward the Missouri River since 2 specimens from eastern Nebraska, a juvenile from Webster County and an adult from Lancaster County, are both typical paradoxus." I have examined the specimen from Webster County referred to by Glass and agree that it is paradoxus. I have not seen the specimen from 9 mi. NW of Lincoln; however, another specimen from there, two others from Lancaster County, and one from Seward County (see above), are here referred to P. h. spilotus, rather than P. h. paradoxus, on the basis of notably darker dorsal coloration and smaller external and cranial measurements. The range of P. h. spilotus in Nebraska, as presently known, therefore, is limited to the eastern, more humid part of the State, south of the Platte River.
Peromyscus maniculatus osgoodi Mearns. Deer Mouse.—Swenk (1908:95) reported this subspecies, under the name Peromyscus nebrascensis, from Glen, and Dice (1941:17) reported the subspecies from Agate, both localities being in Sioux County in the northwestern part of the State. Osgood (1909), however, did not mention Nebraskan specimens of this subspecies and excluded it from the State on his (op. cit.) distribution map of the subspecies of P. maniculatus. In addition, Quay (1948:181) reports, as P. m. nebrascensis, deer mice obtained by him in the badlands of northern Sioux County and adjacent Niobrara County, Wyoming. Four deer mice referable to P. m. osgoodi have been obtained from several localities on the Pine Ridge in Dawes County as follows: 3 mi. E of Chadron, 2; Chadron State Park, 1; 3 mi. SW of Crawford, 1. When compared with specimens of P. m. nebrascensis, geographically adjacent to the east, these mice are seen to be notably darker and less buffy than nebrascensis and to average significantly larger in both external and cranial measurements. All deer mice from the Pine Ridge and adjacent badlands of extreme northwestern Nebraska probably are best referred to P. m. osgoodi. External measurements of two adult females are respectively: Total length, 180, 175; length of tail-vertebrae, 78, 74; length of hind foot, 19, 20; length of ear, 17, 16.
Neotoma floridana campestris J. A. Allen. Florida Wood Rat.—Five wood rats from 5 mi. N, 2 mi. W of Parks, Dundy County, in extreme southwestern Nebraska, provide the first record of occurrence of this subspecies in Nebraska. These animals were trapped in outlying sheds at the Rock Creek State Fish Hatchery. Two large wood-rat houses were in a dense thicket of brush and young trees in a small draw on the west side of the most westwardly hatchery lake. Brown rats (Rattus norvegicus) inhabited a combination garage-storage barn at the hatchery and no wood rats were taken there.
Microtus pennsylvanicus pennsylvanicus (Ord). Pennsylvania Meadow Mouse.—This subspecies occurs in eastern and central Nebraska (see Bailey, 1900:18 and Swenk, 1908:104). Additional records of occurrence are as follows: 5 mi. E of Rising City, Butler County, 5; 4 mi. SE of Laurel, Cedar County, 1; Wayne, 2, and 2-1/2 mi. E of Wayne, 1, Wayne County; 2-1/2 mi. N of Ord, Valley County, 4.
Synaptomys cooperi gossii (Coues). Cooper Lemming Mouse.—Fichter and Hanson (1947:1-8) reported the first known occurrence of this microtine in Nebraska, recording specimens from several localities in Lancaster County and one from near Valentine, Cherry County. Recent records of this mouse which help to clarify its distribution in Nebraska are as follows: 4 mi. N, 1/2 mi. E of Octavia, Butler County, 1; 5 mi. N, 2 mi. W of Parks, Dundy County, 1; 1 mi. N of Pleasant Dale, Seward County, 1.