290 University of California Publications in Zoology. [VL-5 
brown; rostrum longer; mandible less massive; interparietal dif- 
ferently shaped; bullae more swollen; dorsa] and sa anterior 
roots of zygomatic arch narrower. Y 
The ranges of nevadensis and desertorwm as known at pres- 
ent are separated by a wide stretch of territory. Taking this 
fact into consideration, and noting also that nevadensis inhabits 
a different life-zone and possesses a large number of important 
differential cranial characters, the conclusion that it should be 
accorded full specific rank seems amply justified. 
MeasurREMENTS Or Typr.—( External measurements taken in 
the flesh) : total length, 260 mm.; tail vertebrae, 115; hind-foot, 
30. (See table of comparative measurements. ) 
Descriptive ReMARKS.—Geographical considerations lead to 
the comparison of Neotoma nevadensis with Neotoma desertorum 
(Merriam, Proc. Biol. Soe. Wash., IX, July 2, 1894, p. 125), the 
type locality of which is Furnace Creek, Death Valley, Inyo 
County, California. Upon lining up series of the two animals 
in comparable pelage, one is immediately impressed with the 
average darker color of the Nevada specimens. The back of 
nevadensis 1s Slate-gray washed with seal brown. Desertorum, 
on the other hand, has the back varying from light isabella color 
to pinkish buff. 
In respect to color of breast and belly, our examples of the 
new species are more or less clearly distinguishable from deser- 
torum. In three of the Nevada specimens (nos. 8281, 8282, and 
7885) the chest and inguinal region are white. In all of the 
others, however, there is a suggestion of ochraceous buff, which 
in two specimens (nos. 8283, 8287) amounts to a definite suffu- 
sion. The color is deepest on the breast in front of the fore legs. 
As shown by our series from the Mohave Desert (Antelope Val- 
ley, Victorville, ete.), desertorum has the underparts pure white 
in a majority of cases, although some specimens (no. 6089 in 
particular) present a buffy wash on the belly. Two of the 
individuals (nos. 5995, 6089) have the breast in front of the fore 
legs definitely buffy. 
Neotoma nevadensis presents a characteristic black dorsal tail 
surface, there being some variation in the intensity of the color. 
Qc 
One male specimen (no. 8280) has the dorsal surface of the tail 
A ie 
