1908.] NATURAL SCIENCES OF PHILADELPHIA. 403 



NOTES ON THE DISTRIBUTION OF COLORADO MAMMALS, WITH A DESCRIPTION 

 OF A NEW SPECIES OF BAT (EPTESICUS PALLIDUS) FROM BOULDER. 



BY ROBERT T. YOUNG. 



In the following article I propose (1) to discuss briefly the distribu- 

 tion of the mammals of the mountains of northern central Colorado 

 in their relation to the life zones of that region;^ (2) to point out the 

 apparent movement of some species relative to their centers of dispersal 

 and to give a few facts regarding the little known distribution of 

 certain forms in this State, and (3) to describe a new species of bat 

 from Boulder. 



(1) Distribution of mammals relative to the life zones of northern 

 central Colorado. 



In two recent papers by Ramaley^ and myself^ the life zones of the 

 Rocky Mountains in this region, as determined by the flora, have been 

 mapped out. Does the mammalian fauna of the mountains show the 

 same zonation as does the flora? 



The zones as outlined by Ramaley are as follows : 



1. Plains Zone, below 5,800 feet. 



2. Foothill Zone, from 5,800 to 8,000 feet. 



3. Montane Zone, from 8,000 to 10,000 feet. 



4. Sub-alpine Zone, from 10,000 to 11,500 feet. 



5. Alpine Zone, from 11,500 to 14,000 feet. 



The first of these not being a mountain zone may be omitted from 

 our discussion. The last four correspond to the zones which I, in 

 accordance with the terminology of Merriam* and others, have specified 

 as Transition 1,650-2,400 m., Canadian 2,400-2,850 m., Hudsonian 

 2,850-3,300 m. and Alpine^ 3,300-3,450 m.« 



^ Where the records for any species number very few, I have usually omitted 

 such species from this part of my discussion. 



^ Plant Zones in the Rocky Mountains of Colorado, Science, N. S., Vol. XXVI 

 pp. 642-3. 



^ Forest Formations of Boulder County, Colorado, Bot. Gaz., Vol. XLIV, pp. 

 321-52. 



* Life Zones and Crop Zones of the United States, Bull. 10, U S. Biological 

 Survey. 



^ Merriam applies the term Arctic-Alpine to this zone. 



^Ramaley's terminology, as apphed to this particular region, is perhaps more 

 desirable than that of Merriam; but for purposes of comparison -nith other regions, 

 and for the sake of uniformity, I much prefer the latter. 



