1936] MAMMALS OF OREGON 201 



bia to New Mexico, and into the Blue Mountains and Cascades of 

 Oregon (fig. 41). In Oregon they are represented by specimens from 

 Wallowa Lake and Aneroid Lake in the Wallowa Mountains, from 

 north of Harney in the Blue Mountains, and from Diamond Lake 

 and Crater Lake, in the Cascades, but by only 1 or 2 specimens from 

 a locality. These localities are in Canadian and Hudsonian Zones, 

 but the main range of the species is generally considered to be Hud- 

 sonian. Beds of heather and dry slopes of short grass are the more 

 general habitat, but any open, grassy ground, not too wet, suits their 

 purpose. They are rarely found in the dense timber, which occupies 

 most of Canadian Zone, and for this reason are sometimes crowded 

 down to the more open grassy places in the upper edge of Transi- 

 tion Zone, but are more generally found in the parks and meadows of 

 the Hudsonian. 



General habits. Although widely distributed and doubtless far 

 more common than the scattered records indicate, these little gray 

 grass-colored mice are not well known. They burrow in the ground 

 and hide under cover of grass and heather and old logs, so that they 

 are rarely seen alive. Those caught in traps by collectors indicate 

 both nocturnal and diurnal activity and in summer a mainly under- 

 ground residence except when out foraging for food. As the spring 

 snow melts, the winter nests are often found on the surface of the 

 ground where their trails and runways have been covered and pro- 

 tected by deep snows, while the mice ranged for food over the 

 surface of the ground. Their nests are made of fine dry grass, 

 thick walled and clean with soft warm central cavities. Little heaps 

 of winter pellets nearby show good sanitation and also indicate a 

 purely vegetable diet. 



Breeding habits. The adult females have 4 pairs of mammae 

 2 inguinal and 2 pectoral and the number of embryos recorded in 

 those taken for specimens is usually 4, 5, or 6. The dates of these 

 embryos range from May to August, and it is probable that even in 

 the short summer at high altitudes more than one litter of young 

 may be raised in a season. 



Food habits. Like most of the microtines, they feed mainly on 

 green grass and low vegetation, bark, leaves, twigs, and seeds of 

 such plants as grow in their vicinity, and are fond of rolled oats 

 used as trap bait. They usually show no trace of fat but seem to 

 find abundance of food of satisfactory quality at all seasons of the 

 year. 



Economic status. While too small and scarce and scattered to 

 seem to be of any serious economic importance, these little mice fill 

 a niche in the scheme of adjustment in plant and animal life that 

 may be of more importance than we now realize. 



PHENACOMYS INTERMEDIUS OLYMPICUS ELLIOT 

 OLYMPIC PHENACOMYS 



Phenacomys olympicus Elliot, Field Columb. Mus. Pub. 30, Zool. Ser. 1 : 225, 

 1899. 



Type, Collected at Happy Lake, Olympic Mountains, Clallam County, Wash., 

 at. 5,000 feet altitude, by D. G. Elliot, August 14, 1898. 



General characters. Slightly larger than typical intermedius, colors duller 

 and darker; upper parts dark buffy gray or dusky gray; lower parts washed 



