RODEJTTIA SACCOMYINAE DIPODOMYS AGILIS. 



415 



cannot be questioned. Although by no means certain that the true D. phillipii of Gray is the 

 California one, it is yet highly probable. 



If there be but two North American species, they would be readily characterized, independently 

 of color, as follows : 



Dipodomys ordii. Tail vertebrae, about 1 times the length of the head and body ; rarely 

 exceeding 5 inches, never 5. Hind feet moderate, not exceeding 1.50 inches, or about one- 

 third the length of the body. 



Dipodomys phillipii. Tail vertebrae about If times the length of the head and body ; always 

 exceeding 5 inches, usually from 6 to 7 inches. Hind feet larger, usually exceeding 1.60 

 inches, or more than one-third the length of the body. 



There would then remain, as generic characters, the yellowish brown to dusky brown 

 back, the white belly, white line across the thighs, the dark stripes on the upper and under 

 surface of the tail, with the intervening white lateral one on either side. The dusky line under 

 the hind foot is also common to both. 



List of specimens. 



The following species of Dipodomys, indicated very briefly by Dr. Leconte, I know nothing of. 



DIPODOMYS HEERMANNII, Leconte, Pr. A. N. Sc. Phil. VI, April, 1853, 224. 



Tail as long as the head and body ; hair at the tip scarcely longer ; antitragus very short, 

 indistinct. Tail brown, becoming black towards the extremity, with a broad white vitta on 

 each side ; tip, pure black. Specimen not quite adult. Sierra Nevada, collected by Dr. Heer- 

 mann. 



DIPODOMYS WAGNERI, Leconte, IB. 



Based on a specimen in the Philadelphia Academy, labelled " James Keed, South Carolina." 

 As no species are known east of the eastern base of the Kocky Mountains, this is probably an 

 error, if intended to indicate a locality. Supposed to belong to the division with tail much 

 longer than the head and body. Agrees in color with D. agilis. Ears larger, antitragus large, 

 broad, and obtusely rounded at its summit. Outer portion of tail wanting. 



