286 University of Calif onda Publications in Zoologtf. [Vol. 7 



f'oniia. The oeciirreiiee of siu-h a large inniil)ei' of species in an 

 area comparatively small leads to the conchision that the jumping 

 mice are a plastic group of mammals. The Pine Forest ^loun- 

 tain animal is at present limited so far as known to one range 

 of desert mountains. Its evident variation from typical (>)■< (jotius, 

 coupled with its geograi)hic and topographic situation, proclaim 

 it at least a well-marked local race of that form. 



Distribution. — Jumi)ing mice were taken along streams from 

 6000 to 8400 feet altitude in the Pine Forest Mountains. By 

 localities they Avere recorded as follows: head of Big Creek (8000 

 feet), 13; Alder Creek (6000 feet), 2; meadow near Dutfer Peak 

 (8400 feet), 1 ; and Leonard Creek (6500 feet), 2. These points 

 of capture lie in Transition and Canadian ( ?) life-zones. 



The present records extend the range of Zapus p. oregonus 

 very materially. Preble in his list of material examined (1899, 

 p. 24) mentions the following localities : Blue ]\Iountains of 

 Oregon (Harney, Elgin, Strawberry Butte), and Mountain City, 

 northern Ellco County, Nevada. He remarks that the single speci- 

 men from the latter point is not typical. The geographic distrib- 

 ution of the subspecies is given as the "Blue Mountains of 

 Oregon." 



Habits. — As will have been observed, most of our jumping 

 mice were captured at the head of Big Creek. IMost of these were 

 taken very near the stream. One was caught in a comparatively 

 dry place under a sagebush twenty feet from the creek. The 

 jumping mice and the cantankerous meadow mice were for the 

 most part caught in similar situations. 



We were very much surprised to find Zapus on Alder Creek 

 at as low an altitude as 6000 feet. One trapped at this locality 

 was taken under a sagebush thirty feet from the water, the other 

 under a willow close to the stream. At Leonard Creek one was 

 caught about twenty feet from the stream by a rock on sandy 

 soil, another on the immediate bank. 



Thi-ee juvenals (nos. 7995, 7996 and 7998) were secured, the 

 first two at Alder Creek (altitude 6000 feet) on July 16, and the 

 third at the meadow on Duffer Peak (8500 feet), on August 1. 

 On June 26 a female containing five embryos was secured at the 

 head of Big Creek. On the next day one having mammary glands 



