(2) Alcorn 1939. Dipodomys ordii columbianus Swingle Bench District, 4000 ft., 10 mi. W Fallon, Churchill Co., Nevada. This species of rat picked up after poisoning operations are as follows. March 22. 4 M's 1 F with 4 embryos 1/2 developed. March 24. 3 M's 8 F's as follows F 5 embryos 9/10 developed F 4 embryos 9/10 developed F 4 embryos 9/10 developed 5 F's enlarged flabby uterus horns- mammae developed. 2 mi. NW Soda Lake, 4000 ft, Churchill Co., Nevada. March 29. Rats picked up after poisoning operations March 29. as follows. 36 total 15 F's and 21 M's. F's as follows. 1 F had 5 embryos 2 F's had 3 embryos 3 F's had 4 embryos 5 F's had normal uterus horns- no embryo or young. 3 F's had enlarged uterus horns- 1 F Being suckled - mammae developed. March 30 5 M's 3 F's as follows 1 F with 3 embryos 1 F with 4 embryos 1 F with normal uterus horns, no embryo.