Quast 1948 Perognathus spinatus 3 May 15 two mile N of La Paz, Sea Level, Baja California rocky hillside east of camp. Growing in that area were Ironwood, Elaphrium, Opuntia cholla, Lumboi and Cardone. Specimen had enlarged testes. May 16 Same Location. One male (#184) caught on rocky hillside east of camp last night. May 17 Trujillo, 1700 ft, Baja California Six males + one female caught last night in inside of brush fence surrounding an abandoned cornfield about 100 yards long and 30 yards wide. Field was of sandy soil surrounded by rocky soil on which the fence was built. All the P. spinatus were caught on or near the rocks. All the males had enlarged testes; the female had no embryos. Specimens catalogued no. 187-193 incl. All the specimens here were larger and heavier than those of the La Paz district and parts north of that. May 18 Same Location. 45 live traps set in same location as previous night (see paragraph above) yielded 3♂ (#200, 201, 205) and 4♀ P. spinatus. None of the female were pregnant although one was lactating. All males had enlarged testes. May 20 Same Location. Three males and one female (#220-223 incl.) caught in same location last night as traps had been set twice before, namely along brush fence just east of camp. The female had no embryos.