Alcorn 1939 Mus musculus 2 1/2 mi. W Hazen, Truckee Canal, Lyon Co., Nevada. Nov. 12. In the weeds along the Truckee canal many runs may be seen & in these runs the House mouse was caught. The grass is nice & green on southern exposure and it has grown up 4 to 6 inches because the exposure & the water help to keep the grass from freezing in these cold nights. On two occasions these mice were caught in traps that were set 6 to 10 inches from where Reithrodontomys were caught and apparently these 2 species of mice were living in the same habitat and both thriving nicely.