46 University of California Publications i)i Zoology [Vol. 21 



Perodipus leucogenys, new species 

 Pale-faced Kangaroo Rat 



Type.—K&le adidt, skin and skull; no. 26933, Mns. Vert. Zool. ; 

 5600 feet altitude, Pellisier Ranch, five miles north of Benton Station, 

 Mono County, California; September 20, 1917; collected by J. Dixon; 

 original no. 6371. 



Diagnosis. — A large kangaroo rat, closely similar to Perodipus 

 panamintinus Merriam in size and general appearance, but differing 

 in paler tone of coloration, greater extent of white markings, more 

 heavily haired tail, slightly smaller bid.lae, and heavier rostrum. 



Coniparisons. — More in detail, Perodipus leucogemjs differs from 

 P. panamintinus as follows : less black or dusky and more white about 

 face and ears (white spot above eye larger, cheek whiter, forehead 

 paler, light patch on upper rim of ear whiter and larger, dark nose 

 markings less distinctly black) ; white bar across thigh broader; tone 

 of coloration more pinkish buff, with less of dusky intermixture down 

 middle of back; tail distinctly crested to nearly or quite halfway from 

 tip to base ; white side-stripes of tail broader, in other words, black 

 stripes narrower and the lower one of these playing out short of tip 

 of tail; feet (in fall specimens at least) more densely haired. From 

 P. mohavensis Grinnell, P. leucogenys differs in darker, less brightly 

 ochraceous-buff body color, generally larger size, bushier tail toward 

 end, relatively heavier rostrum and dentition, and broader supra- 

 occipital. 



Measurements. — The average measurements of ten adult and sub- 

 adult specimens, five males and five females, are as follows : total 

 length 301 mm. ; tail vertebrae 176 mm. ; hind foot 45.2 mm. ; ear, from 

 crown, 12.4 mm. ; greatest length of skull 40.4 mm. ; width of skull 

 across bullae 24.3 mm. ; greatest length of nasals 15.4 mm. ; width of 

 rostrum near end 4.4 mm. ; width of maxillary arch at middle 5.4 mm. 



Distribution area. — The sagebrush territory southeast of Mono 

 Lake and about the head of Owens Valley, thence southward, at least 

 along the west side of Owens Valley, as far as vicinity of Indepen- 

 dence. Material is at hand as follows. Mono County: Mono Mills, 

 7300 feet, 10 ; Dry Creek, 6700-6900 feet, near Mono Lake, 3 ; Mono 

 Craters, 6600-7100 feet, 3 ; Pellisier Ranch, 5600 feet, five miles north 

 of Benton Station, 12 ; Benton, 5639 feet, 6 ; Taylor Ranch, 5300 feet, 

 two miles south of Benton Station, 29. Inyo County: Farrington 

 Ranch, 4100 feet, west of Laws, 9 ; Walters Ranch, 3900 feet, two 

 miles north-northwest of Independence, 19. 



Perodipus monoensis, new species 



Mono Kangaroo Rat 



Type. — Female adult, skin and skull ; no. 27002, Mus. Vert. Zool. ; 

 5600 feet altitude, Pellisier Ranch, five miles north of Benton Station, 

 Mono County, California ; September 21, 1917 ; collected by J. Dixon ; 

 original no. 6384. 



