Alcorn 1939. Dipodomys merriami merriami. Swingle Bench District, 10 mi. W. Fallon, 4000 ft., Churchill Co., Nev. March 22 After government poisoning (squirrel) operations on desert lands adjacent to cultivated fields I picked up this species of rat and noted the following data. 5 ♀'s + 10 ♂'s were found over about a 40 acre tract. Females as follows ♀ 4 embryos 9/10 developed ♀ 3 embryos 8/10 developed ♀ 3 embryos 1/2 developed ♀ Enlarged uterus horns - no embryos. ♀ Normal - no embryo. March 24 54 rats were picked up in same general locality and 30 were males (30) and, 24 were females as follows. 2 ♀'s had enlarged uterus horns. 2 ♀'s were being suckled + had flabby uterus horns. 2 ♀'s were being suckled - Udder contained fluid. 7 ♀'s had normal udder + uterus, no embryos. 2 ♀'s had 4 embryos each that were 9/10 developed. 3 ♀'s had 3 embryos each that were 5-m. m. long (dia.) 1 ♀ had 2 embryos 9/10 developed 1 ♀ had 3 embryos 8-m. m. long 2 ♀'s had 4 embryos each 3 m. m. long 1 ♀ had 2 embryos 9/10 developed >1 ♀ had 3 embryos 5/10 developed.