104 



NOETII AMEEICAIT FAUNA. 



[NO. 39. 



Distrihution. — Canadian Zone on Bighorn Mountains, Wyo. (fig. 10). 



Characters. — Size about the same as clusius or slightly smaller ; color 

 darker, more rufescent, without gray cheeks and sides; skull with 

 smaller bullae and wider interparietal; mammae in 6 pairs. 



Color, — Summer pelage (September): Upperparts warm grayish 

 brown, with plumbeous nose and black ear patch; underparts rich 

 buffy with white on chin and sometimes on breast; feet soiled whitish; 

 tail gray or buffy with whitish tip. Winter pelage (on rump of type, 

 June 10): Dark buffy gray, underparts creamy. 



SJcull. — General form similar to that of clusius but with shorter, 

 wider interparietal, slightly smaller bullae, and generally wider and 

 more emarginate nasals. 



Measurements. — Type ( $ young ad.): Total length, 196; tail ver- 

 tebrae, 54; hind foot, 26. Topotype ( ? more fully ad.): 203, 58, 28. 

 SJcull (of type): Basal length, 32.5; nasals, 12; zygomatic breadth, 

 20.5; mastoid breadth, 18; interorbital breadth, 6; alveolar length 

 of upper molar series, 6.2. 



Remarlcs. — This form is poorly represented, but shows characters 

 that exclude it from any of the neighboring forms. Externally it 

 most closely resembles the Black Hills gopher, but in cranial charac- 

 ters stands nearest to clusius, of which it may be considered a dark- 

 colored mountain race. A good series of specimens including adult 

 males from the high central area of the Bighorn Mountains will 

 doubtless show more pronounced characters. The details of the 

 distribution of the form remain to be worked out. The specimens 

 examined are aU females and from the Canadian Zone. 



Specimens examined. — Total number, 4, as follows: 



Wyoming: Bighorn Mountains (9,000 and 9,500 feet altitude, in central part), 

 2; Bighorn Mountains (8,400 and 9,000 feet, in southern part), 2. 



THOMOMYS TALPOIDES PRYORI Bailey. 

 Pryor Mountain Pocket Gopher. 



(PI. VII, fig. 7.) 



Thomomys pryori Bailey, Proc. Biol. Soc. Washington, XXVII, 116, July 10, 1914. 



Type. — Collected on Pryor Mountains, Montana, at head of Sage 

 Creek (6,000 feet altitude), by Vernon Bailey, July 16, 1894. Type 

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



Distrihution. — Pryor Mountains, Mont., east to the Bighorn River, 

 near Fort Custer (fig. 10). 



Characters. — Size of clusius, but darker colored and with shorter 

 nasals and more projecting incisors; mammae in 6 pairs, inguinal 2-2, 

 abdominal 2-2, pectoral 2-2. 



Color. — -Summer pelage: Upperparts dull walnut-brown, about as 

 in fossor; nose plumbeous; cheeks dark gray; ear patch black; 



