252 University of California Publications in Zoology. [Vol. 



Measurements of Microtu.'i morda.r. All From the Pine Forest Mountains, 

 Humboldt County, Nevada. 



For method of tiiking measurements, see Introdiictidii. 

 All dimensions are in millimeters. 



Extern.il Cranial o 



A. A ^ 



^ S. -.E " 



^ ti, -Z ^ ^■^ .i >.^ c« 



I ^ Locality 3 :^ 1 |S S S? |? || 1 = 



7974 c? Head of Big Creek 162 61 19 22.5 7.0 14.1 11.9 6.2 31.1 



7975 J' Head of Big Creek 168 63 22 23.4 7.2 13.9 11.9 6.3 34.9 



7977 (^ Head of Big Creek 155 57 20 22.1 7.3 13.3 11.4 6.1 35.1 



7978 J' Head of Big Creek 171 61 22 23.8 8.1 14.7 12.3 6.0 36.1 



7981 J' Leonard Creek 159 60 21 21.0 7.1 13.3 10.9 6.2 35.0 



7982 J' Big Creek Ranch* 177 67 21 31.3 



7976 $ Head of Big Creek 156 57 19 21.2 6.5 10.9 5.9 33.3 



7979 5 Head of Big Creek 163 63 20 22.5 7.3 11.9 6.0 31.7 



7980 2 Meadow. Duffer Pk. 165 57 22 7.1 14.2 6.4 38.6 



Average of the males 165.3 61.6 20.8 22.56 7.34 13.86 11.68 6.16 33.91 



Average of the females 161.3 59.0 20.3 21.85 6.96 14.20 11.40 6.10 34.53 



Average of all the adnlts 164.0 60.6 20.6 22.35 7.20 13.91 11.60 6.13 34.12 



* Big Creek Ranch is on the plain near the mountains, but is at a considerably less alti- 

 tude than the other localities mentioned. 



Duffer Peak meadow (8400 feet), and six days later on Leonard 

 Creek (6500 feet). 



The species has been recorded from the Pine Forest Range 

 before (see Bailey, 1900, p. 50). 



Habits. — The meadow mice were in no ease caught at any 

 distance from streams, ordinarily only a few feet therefrom. They 

 were fairly common at the head of Big Creek. The fact that 

 there was more vegetation there than at other localities in the 

 mountains visited may have had something to do with this. Sev- 

 eral were seen from time to time along the stream during the 

 day, so they are by no means entirely nocturnal. Under such 

 circumstances they kept well within the vegetation at the water's 

 edge. 



From the discovery of freshly cut grasses near the points of 

 capture of Microtus, it may be safely concluded that grass is one 

 item in their diet. The specimen secured on the Duffer Peak 

 meadow was caught iicjii' a small burrow in a da in]) meadow near 

 a stream. 



