FIELD BOOK OF MAMMALS 



Fasciatus Group 



Maximilian Pocket Mouse. — Perognathus fasciatus fasciatus 

 Wied. Plate XXVI. 

 As described above. Found in Upper Sonoran and Transi- 

 tion Zones of eastern Montana and Wyoming, east into the 

 adjoining parts of North and South Dakota. 



Bufif-bellied Pocket Mouse. — Perognathus fasciatus infraluteus 

 (Thomas). 

 Smaller than typical fasciatus, pelage not as soft, yellowish 

 buff instead of white below. Total length, 5.1 inches; tail 

 vertebrae, 2.2 inches; hind foot, .68 inch. Found in Larimer 

 County, Colorado. 



Sweetwater Pocket Mouse. — Perognathus fasciatus litus Gary. 

 Slightly smaller than typical fasciatus, very pale in color, 

 pelage very soft. Upperparts (September pelage) very 



^v 



Fig. 62. Head of Pocket Mouse to show external cheek- 

 pockets 



pale cream buff, sparingly mixed with black; ring around 

 eye, spot at base of ear, and lateral line pale cream buff; 

 feet white; tail faintly bicolor, above slightly dusky, below, 

 white; underparts clear white. Total length, 5.1 inches; 

 tail vertebrse, 2.4 inches; hind foot, .72 inch. Found only 

 in the lower Sweetwater Valley and adjacent parts of Red 

 Desert, Wyoming. 



Plains Pocket Mouse. — Perognathus fiavescens fiavescens 

 (Merriam). 

 Similar to fasciatus but with harsher pelage and less oliva- 

 ceous in color; upperparts light grayish buff mixed with 

 dusky; tail indistinctly bicolor; feet and legs white. Total 

 length, 5.2 inches; tail vertebrse, 2.5 inches; hind foot, .7 

 inch. Found in "Upper Austral plains of South Dakota, 

 Nebraska, and Kansas; south possibly to northern Texas, 

 and west to base of Rocky Mountains." (Osgood) 



Cope Pocket Mouse. — Perognathus fiavescens copei (Rhoads). 

 Resembling typical fiavescens but brighter in color. Upper- 

 parts fawn mixed with blackish, rump and thighs with 

 strong wash of cinnamon; tail grayish white above, pure 



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