94 



NORTH AMEEICAN FAUNA. 



[NO. 39. 



probably separated by lower country from the range of peregrinus, 

 its nearest relative. There is considerable variation in its extension 

 northward to northern Chihuahua but no indication of its intergra- 

 dation with intermedius, which is very similar in general appearance 

 but which with its 4 pairs of mammae and narrow, slender skull, 

 belongs to the fulvus group. 



Specimens examined. — Total number, 117, as follows: 

 Chihuahua: Chuichupa, 1; Colonia Garcia (6,400 feet altitude), 13; near Guad- 

 elupe y Calvo (at 7,000 feet), 6; Pacheco, 11; Sierra Madre (65 miles east of 

 Batopilas at 7,000 feet), 5. 

 Durango: Chacala (3,000 feet), 1, immature; Coyotes, 3; El Salto (8,400 feet), 



10; La Boca, 1; Eio Sestin, 1. 

 Guanajuato: Santa Rosa (8,500 feet), 9. 



San Luis Potosi: La Tinaja (6,000 feet), 8; San Luis Potosi, 1. 

 Sinaloa: Sierra de Choix (50 miles northeast of Choix at 5,000 feet), 3. 

 Sonora: Alamos (1,200 feet), 5. 

 Tepic: Santa Teresa (6,800 feet), 10. 



Zacatecas: Berriozabal (6,600 feet), 10; Plateado, 4; Sierra Madre (8,500 feet), 

 5; Valparaiso Mountains (8.700 feet), 10. 



THOMOMYS GOLDMAN: Meeriam. 

 Goldman Pocket Gopher. 



(PI. VI, fig. 10.) 



Thomomys goldmani Merriam, Proc. Biol. Soc. "Washington, XIV, 108, July 19, 1901. 



T?/2?6.— Collected at Mapimi, Durango, Mexico, by E. A. Goldman, 

 December 15, 1893. Type specimen in U. S. Nat. Mus., Biological 

 Survey collection. 



Distribution. — Eastern Durango, from Mapimi south to Durango 

 City (fig. 9). 



Characters. — Size small, hind foot 27-30 mm. ; color bright tawny 

 above, white below; ears minute; skull short and wide, with project- 

 ing incisors; mammae in 3 pairs, inguinal 2-2, pectoral 1-1. 



Color. — Upperparts bright tawny, darkening on head and becoming 

 dusky around nose and ears; underparts, tip of tail, and lower part 

 of feet, white. 



SJcull. — Short and wide with very short nasals and projecting in- 

 cisors; zygomatic arches slender, nearly parallel, abruptly con- 

 stricted at posterior base; basioccipital wide and flat; nasals nearly 

 truncate, falling slightly short of posterior tips of premaxillge; front- 

 als wide, pushing slightly into base of zygomata; lachrymal lying 

 mainly against base of zygoma, as in umbrinus. 



Measurements. — Type ( j ad.): Total length, 208; tail vertebrae, 

 68; hind foot, 30. Female topotype: 190, 60, 27. Slull (of type): 

 Basal length, 33; nasals, 12; zygomatic breadth, 22; mastoid breadth, 

 18; alveolar length of upper molar series, 7. 



Remarlcs. — The specimens from Mapimi exhibit the extreme differ- 

 entiation of the form. Those from Durango are darker, more nearly 



