74 



NORTH AMERICAN FAUNA. 



[no. 39. 



Measurements. — Type ( c? ad.): Total length, 242; tail vertebrae, 

 64; hind foot, 33. Average of 3 topotypes (9 ad.): 216, 66, 30.3. 

 S'kull (of type): Basal length, 41; nasals, 15; zygomatic breadth, 2S; 

 mastoid breadth, 23; alveolar length of upper molar series, 9. 



RemarTcs. — In color canus closely resembles the gray phase of its 

 near neighbor nevadensis, but shows no relationship with it in cranial 

 characters, while it does agree closely with the perpallidus group. It 

 inhabits moist fertile soil of alkaline vaUeys, with many interruptions 

 in range and some variation in characters. Specimens from Clover- 

 dale, Peavine, and Monitor Valley, Nev., could almost as weU be 

 referred to aureus. 



Specimens examined. — Total number, 43, as foUows: 

 California: Amedee (Lassen County), 1; Fort Sage, 1. 



Nevada: Carson River (Ragtown), 2; Carson Sink, 2; Cloverdale, 7; Deep Hole, 

 5; Fallon, 3; Flowing Spring, 1; Granite Creek, 2; Monitor Valley, 1; Pea- 

 vine, 4; Pyramid Lake (south end), 9; Smoke Creek. 4; Wadsworth, 1. 



THOMOMYS PERPALLIDUS AUREUS Allen. 

 Yellow Pocket Gopher. 



(PL n, fig. 4; PL V, fig. 5.) 

 Thomomys aureus Allen, Bui. Am. Mus. Nat. Hist., V. 49, Apr. 28, 1893. 



Type. — Collected at Bluff, San Juan County, Utah, by Charles P. 

 Rowley, May 12, 1892. Type specimen in Am. Mus. Nat. Hist. 



Distribution. — Desert region of southern Nevada, southern Utah, 

 western Colorado, central and northwestern New Mexico, and north- 

 ern and western Arizona (fig. 8). 



Characters. — Size rather large; hind foot 29-32 mm.; ear relatively 

 small; color golden buff; skull heavy, long, high, and narrow, with 

 palate greatly arched between the molar series ; mammae in 4 pairs, 

 inguinal 2-2, pectoral 2-2. 



Color. — Winter pelage: Upperparts beautiful orange-buff, varying 

 to paler and darker shades and sometimes with a wash of dusky along 

 the back; ear patch and nose blackish in the darker and slightly 

 dusky in the lighter individuals; underparts, feet, and tail creamy 

 white. Summer pelage: Slightly darker. Young, more grayish. 



Slcull. — Long and narrow, with light lateral ridges parallel or some- 

 times nearly meeting in a sagittal crest in extreme old age ; outline of 

 palate strongly arched; bullae full and rounded; interpterygoid fossa 

 normally U-shaped with a central point or spicule extending from 

 median ridge of palate; nasals cuneate and usually truncate pos- 

 teriorly. Dentition heavy; upper incisors abruptly decurved at right 

 angles to skull. 



Measurements. — Average of 5 old male topotypes: Total length, 

 240; tail vertebrae, 73; hind foot, 31. Average of 5 old females: 

 224, 78, 30. Slcull (of topotype, c? ad.):i Basal length, 42; nasals, 



iNo. 57162, U. S. Kat. Mus. 



