116 



NORTH AMEEICAN FAUNA. 



[no. 39. 



above usually to the tip. Winter pelage: Slightly grayer. Young, 

 more huffy. 



Slcull. — ^More hke that of quadratus than of fuscus or monticola; 

 lateral ridges parallel in adults; nasals truncate posteriorly; inter- 

 parietal broadly triangular. Dentition lighter, and incisors less 

 abruptly decurved than in quadratus , fuscus , or monticola. 



Measurements. — Average of 3 topotypes ( c? ad.) : Total length, 

 191; tail vertebrae, 58; hind foot, 25.3. Average of 3 adult females: 

 194, 58, 25. Slcull (of type, c? ad.): Basal length, 31; nasals, 11; 

 zygomatic breadth, 20; mastoid breadth, 17.5; alveolar length of 

 upper molar series, 6. 



Remarlcs. — The subspecies ^s/ieri is typical only along the western 

 part of its range. In central Nevada it is darker and perhaps grades 

 into uinta. In northwestern Nevada it grades imperceptibly into 

 quadratus, the only form with which it seems to be closely connected. 

 It is quite distinct from monticola, with which it occurs at the type 

 locality, and from which it differs in much smaller ears and paler 

 color. 



Specimens examined. — Total number, 97, as foUows: 

 CaUfomia: Beckwith, 1; Casa Diablo, 6; Mono Lake, 8; Sierra Valley, 8. 

 Nevada: Arc Dome, 2; Big Creek 6; Bull Run, 2; Cottonwood Range, 14; 

 Eureka, 3; Monitor Mountains, 2; Mount Siegel, 2; Mount Sugar, 6; Pine 

 Forest Range, 4; Reese River Valley (50 miles south of Austin), 9; Reno, 6; 

 Ruby Lake, 3; Ruby Mountains, 2; Silver Creek (north of Austin), 5; Sum- 

 mit Lake, 3; Verdi, 3; Wells, 2. 



Thomomys douglasi Group. 



THOMOMYS DOUGLASI DOUGLASI (Richardson). 

 Douglas Pocket Gopher; Columbia Sand Rat. 



(PI. II, fig. 10; PI. VIII, fig. 5.) 



Geomys douglasii Richardson, Fauna Boreali- Americana, I, 200, 1829. 

 Geomys Juliginosus Schinz, Syn. Mamm., II, 136, 1845. "Habitat ad fluvium 

 Columbia." 



Thomomys douglasii Allen, Bui. Am. Mus. Nat. Hist., V, 66, April 28, 1893. 



Type. — Collected ''near tbe mouth of the Columbia," at Fort 

 Vancouver, Washington, by David Douglas, probably in 1825. Mr. 

 Oldfield Thomas writes that it is not now in the British Museum 

 collection. 



Distribution. — Known only from type locahty (fig. 5). 



Characters. — Size medium; claws stout; ears medium with rounded 

 tips; color nearly uniform dull hazel without dark ear patch; skull 

 long and slender and flat on top; incisors abruptly decurved and 

 distinctly grooved; mammse in 4 pairs, inguinal 2-2, pectoral 2-2. 



Color. — (June specimens from type locality): Upperparts uniform 

 dull hazel, shghtly paler on sides; underparts more ochraceous, with 



