248 Univfrsify of California PuhJicafious i)) Zoologi/. [Vol.7 



Measurements of Neotoma desertomm From the California Side op 

 THE Colorado Eiver. 



For method of taking measurements, see Introduction. 



All dimensions are in millimeters. 



Total Tail Hind 



Locality length vertebrae foot 



20 miles above Picacho 273 137 31 



Opiwsite the Needles 298 140 30 



20 miles above Picaeho 225 115 30 



20 miles above Picacho 295 138 30 



Near Pilot Knob 275 120 30 



Opposite Cibola 286 137 29 



Average of all the adults 275.3 131.1 30.0 



Average of Neotoma nevadensis 257.6 111.7 30.3 



Upon looking over the skins of the two series, differences are 

 even more clearly apparent. Nevadensis is shown to be a good 

 shade darker than desertomm. The entire series of the latter 

 averages lighter, and this holds for very young ones as well as for 

 adults. As regards coloration of dorsal tail surface only one 

 specimen of desertormn (no. 10437) has the very black dorsal 

 tail surface characteristic of nevadensis. As for dimensions (see 

 table of measurements), comparable desertorum from the Colo- 

 rado River averages 17 millimeters longer as regards total length 

 (7 per cent, greater), and 19 millimeters longer tail vertebrae 

 (17 per cent, greater). These differences are not inconsiderable. 



The characters as a whole, taking into account cranial char- 

 acters, coloration, and difference in size seem to be significantly 

 correlated, and indicate that Goldman (1910, p. 76) is not justi- 

 fied in relegating nevadensis to synonymy. 



Distribution. — Neotoma nevade)isis probably ranges over a 

 considerable portion of the northern part of the Great Basin 

 Region in Nevada. The Washoe County specimens, although not 

 typical, would appear to extend its range westward and south- 

 ward. 



Habits. — The sagebrush is the characteristic plant of the 

 region inhabited by this wood rat. The fact that there are few 

 rocks except on the scattering buttes and in the mountains may 

 be one reason for its rarity. However, it nuist live at least to 

 some extent in burrows in the open ; for one juvenal was caught 

 at Quinn River C-rossing far from rocks of any kind, nor were 



