344 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 



into variety arizonce. 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 TROWBPJDGEI. 



Trowbridge's Hare. 



Lepus trotebritlgei Baird, Proc. Acad. Nat. Sci. Phila., vii, 1855, 333; Mam. N. Am., 1857, G10, pi. xiv, 

 (animal).— Newberry, Pacific R. R. Ex. & Surv., vi, iv, 1857, 65.— Kknnerly, ibid., x, vi, 

 1859, 17.— Cooper, ibid., xii, iii, 18G0, 87. — Gray, Auu. aud Mag. Nat. Hist., 3d ser., xx, 1867, 

 2-24.— Allen, Proc. Bost. Soc. Nat. Hist., xvii, 1675, 434. 



Smallest of the North American Leporidce. Tail very short, almost 

 rudimentary. Postorbital process scarcely in contact with the skull posteri- 

 orly. Ears, head, and hind feet about ecpial 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 L. 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 I 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 L. 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 nuttalli of the middle region 

 of the continent. 



