1936] MAMMALS OF OEEGON 249 



with dusky tips of hairs and clear buff margin along each side; ears dusky 

 with white specks at upper and lower base; feet and lower parts buffy with 

 white on breast ; tail buffy gray above, clear buff below except dusky tip. 



Measurements, Average of typical adults: Total length, 133 mm; tail, 72; 

 foot, 18.7; ear (dry), 6. 



Distribution and habitat. Found in the Upper Sonoran sagebrush 

 valleys of central and northern Nevada, northwestern Utah and 

 southeastern Oregon (fig. 55). Three specimens taken by Streator 

 at Tumtum Lake in 1896 and one by Preble at Rome on the Owyhee 

 Eiver in 1915 are the only records for Oregon. 



General habits. In habits these tiny pocket mice seem to be much 

 the same as parvus, which is twice as large and lives in the same 

 localities. Even their tracks and burrows are easily recognized by 

 their small size, the burrows sometimes being mistaken for those of 

 the mole cricket, Stenopalmatus. They are found under sagebrush 

 or greasewood on mellow soil, but the main entrance is usually kept 

 closed during the daytime and only a tiny mound of earth is seen to 

 mark the place. Where common the animals are readily caught in 

 traps baited with rolled oats and set near their burrows, or in 

 long smooth lines made by scraping the foot over the surface of 

 the ground and with the traps set across these lines. 



Breeding habits. One taken by H. C. Oberholser at Stillwater, 

 Nev., May 7, 1898, contained 4 embryos, and another recorded by 

 Taylor from Big Creek ranch, Nevada, on June 10, 1909, contained 3 

 embryos. 



Family GEOMYIDAE: Pocket Gophers 



THOMOMYS BULBIVORUS (RICHARDSON) 

 CAMAS POCKET GOPHER 



Diplostoma "bulbivorum, Richardson, Fauna Boreali-Amer., v. 1, p. 206, 1829. 



Type. From banks of the Columbia River, Oreg., probably near where 

 Portland now stands. Collector unknown. 



General characters. Largest of the genus ; compact and robust ; ears small, 

 merely thickened rims; eyes small; incisors protruding; tail weak and taper- 

 ing, almost hairless; winter coat long and furry; summer thin and harsh; 

 color dark sooty brown, nearly the same above and below ; chin and anal spot 

 usually white. 



Measurements. Average of adult males: Total length, 300 mm; tail, 90; 

 foot, 42; ear (dry), 5. Average of females: 271; 81; 39; 5. 



Distribution and habitat. Willamette Valley, Oreg., from Port- 

 land and Forest Grove south to Eugene, west to Grand Ronde Valley 

 (fig. 56). Generally common in the more open parts of the valley 

 country but not entering the coniferous timber. 



General habits. These big pocket gophers have relatively rather 

 weak claws for an underground life, but by the use of their protrud- 

 ing incisors they are able to loosen up the hard-baked earth through 

 which they tunnel, and in consequence their large mounds thrown 

 out on the surface of the ground are often a mass of small cakes and 

 lumps of well-baked clay. The burrows are large and extend in end- 

 less labyrinths a foot or two below the surface of the ground, 

 coming to the top at intervals of a few feet to a few rods where the 

 surplus earth is pushed out in little heaps called " gopher hills." 

 The entrance is then securely packed full of earth and the tunnel 

 continued until it is necessary to open a new doorway or one of the 



