88 



NORTH AMEEICAN FAUNA. 



[XO. 39. 



Distribution. — Sierra Blanca, western Texas, north to Tularosa, 

 N. Mex. (fig. 7). 



Characters. — Size medium, hind foot 29-32 mm.; color, dull ochra- 

 ceous-tawny; skull short and wide with projecting incisors; mammae 

 in 4 pairs, inguinal 2-2, pectoral 2-2. 



Color. — Fresh winter pelage: Upperparts dull ochraceous-tawny 

 or buffy fulvous, with dusky ear patch and nose; underparts pale 

 salmon or creamy white; tail huffy to the tip; feet soiled whitish. 

 Summer pelage: Not represented. 



Slcull. — Short and wide, with greatly protruding incisors; basi- 

 occipital wide between the narrow bulla?; premaxillse extending but 

 slightly back of nasals; interparietal quadrate; anterior base of 

 zygoma convex; coronoid process of mandible curved, and post- 

 coronoid notch widely circular. 



Measurements. — Topotype ( ad.): Total length, 215; tail ver- 

 tebrae, 64; hind foot, 31. Average of five females: 212, 69, 29. SlmU 

 (of type): Basal length, 37; nasals, 17.7; zygomatic breadth, 26.5; 

 mastoid breadth, 19; alveolar length of upper molar series, 7.5. 



Remarlcs. — In wide skull and projecting incisors haileyi suggests 

 the umbrinus group, but as no other detailed characters of the group 

 appear the resemblance is evidently accidental. Nine specimens 

 from Tularosa, N. Mex., average larger and darker colored than those 

 of the type series, but show the prominent cranial characters. 

 There is nothing to indicate that the species has a continuous range 

 between these localities, but it is not improbable that it follows 

 along the west base of the Sacramento Mountains in the Upper 

 Sonoran or the upper edge of the Lower Sonoran Zone. The Tularosa 

 specimens suggest a distant connection with the fulvus group. 



Specimens examined. — Total number, 15, as follows: 

 New Mexico: Tularosa, 9. 

 Texas: Sierra Blanca, 6. 



THOMOMYS LACHUGUILLA Bailey. 

 Lachuguilla Pocket Gopher. 



(PI. VI, fig. 8.) 



Thomomys aureus lachuguilla Bailey, Proc. Biol. Soc. Washington, XV, 120, June 2, 

 1902. 



Type. — Collected at El Paso, Texas (in a dry wash in the mountains 

 a mile northeast of the town), by Vernon Bailey, September 24, 1901. 

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



Distribution. — Arid Lower Sonoran mesas in extreme western Texas 

 and southern New Mexico, south to Casas Grandes, Chihuahua (fig. 7). 



Characters. — Size small, hind foot 27-29 mm.; color, dull ochra- 

 ceous-tawny; skull narrow with abruptly decurved incisors; mammae 

 in 4 pairs, inguinal 2-2, pectoral 2-2. 



