344 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
into variety arizone. The latter is as yet known only from Western 
Arizona, but will doubtless be found to extend over the western parts of 
Southern California and southward into Western Mexico, or over a large part 
of the so-called Sonoran district. 
LEPUS TROWBRIDGEI. 
Trowbridge’s Hare. 
Lepus trowbridgei Barrp, Proc. Acad. Nat. Sci. Phila., vii, 1855, 333; Mam. N. Am., 1857, 610, pl. xiv, 
(animal).—NEWBERRY, Pacific R. R. Ex. & Surv., vi, iv, 1857, 65 —KENNERLY, ibid., x, vi, 
224.— ALLEN, Proc. Bost. Soc. Nat. Hist., xvii, 1875, 434. 
Smallest of the North American Leporide. Tail very short, almost 
rudimentary. Postorbital process scarcely in contact with the skull posteri- 
orly. Ears, head, and hind feet about equal in length. Above yellowish- 
brown, varied with dark brown; sides, throat, and chest paler; beneath dusky 
gray, varying to whitish; back of neck rufous. Colors generally darker 
above and more finely blended than in any of the varieties of ZL. sylvaticus. 
The dark long hairs of the back appear to be generally blackish-brown, but 
in some specimens they are decidedly black. 
The specimens before me are the same as those described by Professor 
Baird in 1857, with the exception of a few additional ones from Fort Tejon, 
and [ find little to add to his account. As Professor Baird observes, there is 
considerable variation in respect to the length of the ears in different speci- 
mens and also in color, some specimens being decidedly whitish below 
instead of plumbeous-gray, and with the long dark hairs above decidedly 
black in some cases instead of blackish-brown. 
Its nearest ally is the Lepus sylvaticus var. auduboni, but this form 
rather exceeds it in size, has the ears distinctly edged and tipped with black- 
ish instead of being uniformly gray, is whiter below and of a more yellowish- 
gray above, with the longer black hairs more strongly in contrast with the 
general color. The variations in general color, however, in different individ- 
uals, respectively, of the two forms rather overlap, so that general color is 
not alone distinctively diagnostic. The shorter tail and (apparently) relatively 
shorter hind feet of ZL. trowbridgei are the more especially characteristic 
features. Both forms occur together on the Pacific slope; but L. sylvaticus 
variety auduboni ranges also to the desert plains of Southern Nevada and 
Arizona. where it insensibly blends with variety nu¢talli of the middle region 
of the continent. 
