82 



MONOGRAPHS OF NORTH AMERICAN RODENTIA. 



T.uh.k XIX- 



-Measuretnents of eighty-one (and list of other) specimens of supposed Hebperomys leocopcs 



soNoiui.xsis/cym the Middle Region, United States — Continued. 



mice, both from the Platte region and from Fort Bridger, are all essentially of tbe 

 sonorienttus style. Those from the Platte, like Haydcn's Nebraska and Upper Missouri lots, are very pale and short -tailed, while 



t Drexler's extensive gathering's of mice 



the Utah ones are rather more like leucopus ii color, and the brevity <>i the tail isnot qnite so strongly marked. In limb 

 these series the specimens grade directly into leucoptu. We have, liowever, labeled them all "var. sonoriensis", because the 

 attempt to discriminate has proved utterly Impossible in this as mother similar cases where we have been obliged to label 



iir..- l ni/,fn.;,lh/ -■■' tu spr.lli. Thlfl grathltiolJ Mltll ntillh.iM ItUfOpUS IS 111 Strict ;n n >] ,l:iln'r W 1 1 1 1, :tli. I alliph .iii.lilltis, toil 



mature opinion respecting the "variety ' sonori&ma. 



I tolonel Simpson'* examples, from" Fort Bridgeware pure sonoriensis ,- so are Dr. Hitz's, from Fort Shaw. 



