PEROMYSCUS. 53 



eye including all the underparts white; hands, feet and legs white; 

 tail grayish brown above on basal third, remainder and underpart 

 white; ears edged broadly with white. Type in United States 

 National Museum. 



Peromyscus leucopus aridulus Osgood. 



Peromyscus leucopus aridulus Osgood, N. Am. Fauna, No. 28, 1909, 

 p. 122. 



Type locality. Fort Custer, Yellowstone County, Montana. 



Geogr. Distr. Upper Sonoran Zone of eastern Wyoming and 

 Montana, and the adjacent western parts of South Dakota and 

 Nebraska, probably south of Oklahoma and west to eastern Colorado. 



Gent. Char. Similar to P. I. noveboracensis, but larger and paler; 

 skull larger, braincase wider; nasals broader; molar teeth and audital 

 bullae larger. 



Color. Entire upperparts ochraceous-buff washed with dusky; 

 dorsal line slightly darker; underparts creamy white; hands and feet 

 white; tail above brown, beneath whitish. Ex type in United States 

 National Museum. 



Measurements. Total length, 177; tail, 73; hind foot, 22; ears, 

 14.5. Skull: Occipito-nasal length, 26.2; Hensel, 26; zygomatic 

 width, 14.3; inter temporal width, 4.5; length of nasals, 10; length of 

 upper molar series, 4; length of mandible, 11.3; length of lower molar 

 series, 4.3. Ex type in United States National Museum. 



Peromyscus leucopus ochraceus Osgood. 



Peromyscus leucopus ochraceus Osgood, N. Am. Fauna, No. 28, 

 1909, p. 124. 



Type locality. Winslow, Navajo County, Arizona. 



Genl. Char. Similar to P. I. tornillo, but color different. 



Color. Entire upperparts ochraceous-buff lined with dusky; 

 darkest on middle of back, but not forming a dorsal line; underparts 

 white, tinged with buff; tail above dusky brown, beneath buffy white; 

 feet and hands buffy white; ears edged with creamy white, and wrists 

 marked with ochraceous-buff. Ex type in United States National 

 Museum. 



Measurements. Total length, 180; tail, 82; hind foot, 22.5. 

 Skull: Occipito-nasal length, 26.5; Hensel, 21.1; zygomatic width, 

 14.5; intertemporal width, 3.9; length of nasals, 10; length of upper 

 molar series, 3.8; length of mandible, 13.7; length of lower molar 

 series, 4.4. Ex type in United States National Museum. 



Peromyscus leucopus mesomelas Osgood. 



Peromyscus texensis mesomelas Osgood, Proc. Biol. Soc. Wash., 

 XVII, 1904, p. 57. 



