80 



NORTH AMERICAN FAUNA. 



[NO. 39. 



THOMOMYS SINALO^ Merriam. 

 SiNALOA Pocket Gopher. 



(PI. IV, fig. 7.) 



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



Type. — Collected at Altata, Sinaloa, Mexico (altitude 10 feet above 

 sea level), by E. A. Goldman, March 28, 1899. Type specimen in 

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



Distyihution. — Western Sonora and Sinaloa, from Hermosillo south 

 to Albata (fig. 7). 



CJiaracters. — Size rather large, hind foot 30-32 mm.; tail long; 

 pelage thin; color bright tawny; skull heavy, wide, and angular; 

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



Color. — Upperparts bright tawny or dull chestnut with a trace of 

 dusky along back; underparts plain light tawny; nose grayish brown; 

 feet and tail half-naked, half-covered with buffy hairs. Young, 

 paler, more bulfy. Summer and winter colors not very different. 



Slcull. — Heavy, wide, and angular; rostrum wide; nasals short and 

 normally truncate posteriorly; zygomata abruptly spreading; bullae 

 full and rounded; basioccipital narrow between bullae. Dentition 

 heavy;* incisors abruptly decurved. 



Measurements. — Type ( c? ad.): Total length, 233; tail vertebrae, 

 73; hind foot, 31. Average of 3 topotypes ( ad.): 228, 75, 31.5. 

 Average of 3 adult females: 214, 73, 31.3. Sliull (of type): Basal 

 length, 39.5; nasals, 14.5; zygomatic breadth, 28.3; mastoid breadth, 

 22; interorbital breadth, 6.2; alveolar length of upper molar series, 8.2. 



Remarlcs. — Despite fulvous coloration the closest affinities of this 

 form appear to be with the perpaUidus group. From its nearest 

 relative, cervinus, it differs in thin pelage, darker coloration, and short 

 wide skull. Two small females from Magdalena, Sonora, are not 

 typical and can only provisionally be referred to this species. 



Specimens examined. — Total number, 22; as follows: 

 Sinaloa: Altata, 6. 



Sonora: Camoa, 11; Hermosillo, 2; Magdalena, 2; Ortiz, 1. 



Thomomys fulvus Group. 

 THOMOMYS FULVUS FULVUS (Woodhouse). 

 Fulvous Pocket Gopher. 

 (PI. VI, fig. 1.) 



Geomys fulvus Woodhouse, Proc. Acad. Nat. Sci., Philadelphia, VI, 201, 1852. 

 Thomomys fulvus Baird, Mamm. N. Am., 402, 1857. 



Type. — Collected on San Francisco Mountain, Arizona, by Dr. S. W. 

 Woodhouse, October, 1851. Type specimen in U. S. Nat. Mus. 



Distribution. — Transition Zone in northern and central Arizona 

 from the Trumbull Mountains to the White Mountains; east m New 



