1915. ] 



THOMOMYS PEEPALLIDUS GEOUP. 



73 



and gives place to operarius in the bottom of Owens Valley, and to 

 aureus in Ash Meadows and the Amargosa Valley. Its connection 

 with perpallidus on the south has been fully established by recent 

 collections, so that both perpes and aureus must stand as subspecies 

 of this earliest-described form of the desert group. TJiomomys scap- 

 terus of Elliot proves to be typical of perpes. 



Specimens examined. — Total number, 344, as follows: 

 California: Ash Creek (west of Owens Lake), 1; Barstow, 16; Benton Station, 4; 

 Bishop, 1; Cactus Flat, 1; Carroll Creek, 1; Copper City. 1; Coso, 19; Cushen- 

 bury Spring, 2; Daggett, 2; Fairmont, 1; Granite Spring, 1; Grapevine Ranch, 

 3; Haway Meadows (south of Owens Lake), 2; Hesperia, 1; Independence, 13; 

 Independence Creek, 2; Inyo Mountains, 1; Isabelle, 6; Kern River (South 

 Fork, near Onyx), 17; Lone Pine, 64; Lone Willow Spring, 7; Ludlow, 2; 

 Maturango Spring, 1; Mohave River. 4; Morongo Pass, 1; Mount Waterman 

 (north slope in San Gabriel Mountains), 1; New York Mountain (in Provi- 

 dence Range), 1; Orogrande, 16; Panamint Mountains (Johnson Canyon, 

 Perognathus Flat, Coal Kilns, Hanopee Canyon, head of Willow Creek, and 

 Cottonwood Creek), 23; Resting Spring, 24; Tuttle Cree^ 5; Twelve Mile 

 Spring, 1; Victorville, 26; Walker Pass, 28; Warrens Ranch (in Morongo 

 Valley), 1; Warrens Well (east of Morongo Valley), 2; Weldon, 37; White 

 Mountains (pass between Deep Spring and Owens Valley), 1. 

 Nevada: Grapevine Mountains, 3; Thorps Mill, 1. 



THOMOMYS PERPALLIDUS CANUS Bailey. 

 Gray Pocket Gopher. 



(PI. V, fig. 6.) 



Thomomys canus Bailey, Proc. Biol. Soc. Washington, XXIII, 79, May 4, 1910. 



Type. — Collected at Deep Hole, at north end of Smoke Creek 

 Desert, Nevada, by Clark P. Streator, May 14, 1896. Type specimen 

 in U. S. Nat. Mus., Biological Survey collection. 



Distribution. — Valleys of western and central Nevada, from Flow- 

 ing Springs, western Humboldt County, south to Cloverdale and 

 Monitor Valley, west to Honey Lake, Cal. (fig. 5). 



OJiaracters. — Considerably larger than perpallidus, with larger ears 

 and shorter tail; size of aureus or a little larger; hind foot 30-33 

 mm.; colors huffy gray; skull wide, palate flat, not arched between 

 molar series; mammae in 4 pairs, inguinal 2-2, pectoral 2-2. 



Color. — Upperparts pale huffy gray with dusky ear patch and 

 brownish nose; underparts, feet, and tail whitish. The remnant of a 

 more yellowish pelage on the rump of a topotype collected May 16 

 would indicate a darker winter pelage, while an old female collected 

 at Amadee July 24 is coming into a still more ashen gray pelage. 



STcuU. — Much heavier and wider than that of perpallidus; like that 

 of aureus but lower and wider with flat instead of arched palate; 

 interparietal larger and more quadrate; bullae slightly larger; anterior 

 points of frontals less acute; lateral pits of palate deeper. 



