I. ON THE MURIDi: OF THE NORTHERN BOUNDARY SURVEY, 

 WITH A CRITICAL REVISION OF THE NORTH AMERICAN 

 GENERA AND SPECIES. 



The present is the first of a series of preliminary zoological 

 reports which may appear from time to time, during the elabora- 

 tion of the material secured by the Boundarj- Commission. Gen- 

 eral faunal considerations are deferred to the final report. The 

 ground here covered is a belt of country along the parallel of 49° 

 N., from the Red River of the North to the Rocky Mountains, 

 representing the northern border of the Territories of Dakota and 

 Montana, Of North American Jluridae, the genera Higmodor}^ 

 Ochetodon, llyodes, and Cuniculus are not represented, the first 

 two being Southern, the others Arctic. All the genera and species 

 are, however, introduced to complete an account of the group. 



A, Subfamily Murine. 

 {Murine Series.) 

 I. Genus MUS, L. 

 1- Mus decumanns, L. 



Introduced. 



2. Mus musculus, L. 

 Introduced. 



{Sigmodoni Series.') 



II. Genus NEOTOMA, Say and Ord. 



3. Neotoma cinerea, S. & 0. 



Eastern base and outliers of the Rocky Mountains ; not east- 

 ward on the prairie. Frequent. 



III. Genus HESPEROMYS, Woodh. 



(Subgenus Vespekimus, Coues.) 



4. Hesperomys (Vesperimus) cucopus, Lee. 



Everywhere ; the most abundant and characteristic species. 

 Mainly represented by var. sonoriensis. 



