MUEID^. — CLXXXV. 321 



and hind feet ; tail longer. L. 5. T. ^. Lowland swamps, Va, 

 especially the Dismal Swamp. (cXor, swamp ; dXijnjr, wanderer.) 



544. MICROTUS Sohrank. (Field Mice.) (^iKpos, small ; 

 o5j, ear.) 



a. Posterior upper molar with one exterior triangle and a posterior trefoil: 

 middle upper molar with one internal triangle; front lower molar with 

 two internal and one external triangle. 

 b. Fore claws larger than hinder ; fur dense, silky, mole-like ; size small. 

 (Fitymys McMurtrie.) 



1043. M. pinetorum (Le Conte). Pine Mouse. Chestnut 

 color, ashy below. L. 4|-. T. -J. Mass. to 111. and S. The northern 

 form is subspec. soalopsoides (Aud. & Bach.). (Lat., of the pines.) 



ib. Foreclaws not larger than hinder; fur coarse, not glossy; size medium. 

 (Pedomys Baird.) 



1044. M. austerus (Le Conte). Prairie Meadow Mouse. 

 Grizzly brownish, rusty plumbeous below. L. 5J. T. 1. Mich, to 

 Kan., and S. (Lat., harsh.) Subspec. minor (Merriam) occurs 

 in Minn, and Dak. 



1045. M. cinnamomeus (Baird). Similar to ilf. oMsierus, the 

 skull narrower ; yellowish brown above with rufous wash ; belly pale 

 cinnamon ; tail bicolor. L. 4J. T. IJ. Minn. (Lat., cinnamon.) 



aa. Posterior upper molar with two external triangles and a posterior cres- 

 cent ; middle upper molar with two internal triangles; front lower molar 

 with three internal and two or three lateral triangles; size large. 

 {Microtus.) 



1046. M. pennsylvanicus (Ord). Meadow Mouse. Fore 

 claws not longer than hind claws. Grayish brown, blackish me- 

 sially, hoary below. L. 5^. T. li. E. U. S., generally abundant; 

 variable. Subspec. fontigenus (Bangs) from localities in Canada, 

 and subspec. aoadious from Nova Scotia, have been described. 



1047. M. chrotorrhinus (Miller). Slightly smaller than 

 M. pennsylvanicus with broader hind feet; nose patch tawny ochra- 

 ceous; brain case low, broad. White Mts., N. H. ixpas, color; 

 plv, nose.) 



1048. M.breweri (Baird). Size of Af.penn.53/Zuamcusy or larger, 

 paler, yellowish gray, below nearly white. Muskeget Island, Mass. 

 (To Dr. T. M. Brewer.) 



545. EVOTOMYS Coues. (Red-backed Voles.) {tZ, well; 

 oJi, ear; pit, mouse.) 



1049. B. gapperi (Vigors). Red-bached Vole. Median line 

 of back bright chestnut; sides bufiy-ochraceous; belly pale buffy 



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