300 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 



species has been received is Fort Riley, Kansas. Further north, it extends 

 eastward to the .Missouri River and westward nearly to the Pacific coast. 

 Lewis and Clarke observed it on. the plains of the Columbia, where, according 

 to Nuttall (as quoted by Bachman), it is abundant. Townsend obtained 

 Specimens on the Walla-Walla, and Dr. George Suckley on the eastern slope, 

 of the Blue Mountains of Oregon* and on the plains of the Columbia east 

 of the Cascades. Dr. Suckley also speaks of it as occurring on the sage- 

 plains north of Fort Boise. f Dr. J. G. Cooper speaks of it as common south 

 of the Columbia and Snake Rivers, but rare of late years to the northward 

 of these rivers J A single specimen in the collection of the Smithsonian 

 Institution, from Fort Crook, California, indicates its occurrence in Northern 

 California. 1 found it abundant in Salt Lake Valley, Utah, and throughout 

 Southern Wyoming and Northern Kansas eastward to within two hundred 

 miles of the Missouri River. To the northward, it extends to the plains of 

 the Saskatchewan, where, according to Richardson, it is abundant. Dr. Coues 

 brought in specimens collected along the forty-ninth parallel, where he found it 

 common.§ Its limit to the southward is not so well known, but no specimens 

 have been received from south of Middle Kansas and the Great Salt Lake 

 Basin ; south of these points, it is wholly replaced by the L. callotis var. 

 texianus, whose range somewhat overlaps that of L. campestris. ' It is emi- 

 nently a species of the great sage-plains, and its main range seems to be 

 from Middle Kansas northward to the plains of the Saskatchewan, and from 

 the eastern edge of the great plains westward to the Sierra Nevada Mount- 

 ains. 



* Pacific R. R. Rep. & Expl., xii, pt. ii, p. 131. 



t Pacific R. R. Rep. & Expl., xii, pt. ii, pp. 104, 131. 



t Am. Nat., ii, 536. 



$ Dr. Coues bas published a monographic sketch of this species, inadvertently overlooked in pre- 

 paring the bibliographical resume' of the subject which has been given on a preceding page. See Bull. 

 Essex Inst,, vii, 1875, p. 73 et seq. 



