RODENTIA: GEOMYIDAE 331 



Type Locality. — Ten miles east of Chinapa, Rio Sonora Valley, northern So- 

 nora, Mexico. Altitude, 3,000 feet. Range. — Irregularly broken or mountainous 

 region west of Sierra Madre in northeastern Sonora. 



Thomoniys umbrinus eximius Nelson and Goldmanf * 



1934. Thomomys umbrinus eximius Nelson and Goldman, Journ. Mamm., 

 vol. 15, No. 2, p. 118, May 15, 1934. 



Type Locality. — Sierra de Choix, about 20 miles northeast of Choix, Sinaloa, 

 Mexico. Altitude, 5,000 feet. Range. — Upper slopes of Sierra de Choix, a 

 western spur of Sierra Madre, northern Sinaloa. 



Thomomys umbrinus atrovarius J. A. Allen* 



1898. Thomomys atrovarius J. A. Allen, Bull. Amer. Mus. Nat. Hist., vol. 10, 



p. 148, Apr. 12, 1898. 

 1934. Thomomys umbrinus atrovarius Nelson and Goldman, Journ. Mamm., 



vol. 15, No. 2, p. 119, May 15, 1934. 

 Type Locality. — Tatemales, near Rosario, Sinaloa, Mexico. Range. — Coastal 

 plain from southern Sinaloa south to central Nayarit, Mexico. 



Thomomys umbrinus sheldoni V. Bailey f* 



1915. Thomomys sheldoni V. Bailey, North Amer. Fauna No. 39, p. 93, Nov. 



15, 1915. 

 1934. Thomomys umbrinus sheldoni Nelson and Goldman, Journ. Mamm., 



vol. 15, No. 2, p. 113, May 15, 1934. 

 Type Locality. — Santa Teresa, 40 miles east of Acaponeta, Nayarit, Mexico. 

 Altitude, 6,800 feet. Range. — Upper slopes of Sierra Madre from northern 

 Nayarit and extreme western Zacatecas north through western Durango to south- 

 western Chihuahua, Mexico. 



Thomomys umbrinus musculus Nelson and Goldmanf* 



1934. Thomomys umbrinus musculus Nelson and Goldman, Journ. Mamm., 

 vol. 15, No. 2, p. 119, May 15, 1934. 



Type Locality. — Pedro Pablo, about 22 miles east [ = 14 miles east-southeast] 

 of Acaponeta, Sierra de Teponahuaxtia, Nayarit, Mexico. Altitude, 3,500 feet. 

 Range. — Tropical western slopes of Sierra Madre in southern Sinaloa and 

 northern Nayarit, Mexico. 



Thomomys umbrinus extimus Nelson and Goldmanf* 



1934. Thomomys umbrinus extimus Nelson and Goldman, Journ. Mamm., vol. 

 15, No. 2, p. 119, May 15, 1934. 



Type Locality. — Colomo, near Rio de Ameca, southern Nayarit, Mexico. Alti- 

 tude, 600 feet. Range. — Arid tropical coastal plains in extreme southern 

 Nayarit; probably intergrading to the northward with atrovarius. 



Thomomys simulus simulus Nelson and Goldmanf* 



1934. Thomomys simulus simulus Nelson and Goldman, Journ. Mamm., vol. 

 15, No. 2, p. 120, May 15, 1934. 



Type Locality. — Alamos, southern Sonora, Mexico. Altitude, 1,200 feet. 

 Range. — River valleys and foothills up through oak belt of southeastern Sonora 

 (Burt, Univ. Michigan Mus. Zool. Misc. Publ. 39, p. 39, Feb. 15, 1938) . 



