_Specimens examined._--Total, 7, distributed as follows: Los Angeles County: San Antonio Canyon, 4500 ft., 2; San Antonio Wash, 1800 ft., 5 (2 PC). =Neotoma lepida lepida= Thomas Desert Woodrat These woodrats were present in rocky situations along the desert slope from the lower edge of the juniper belt down into the desert. Specimens were taken in piles of boulders in Mescal Wash, and amid rock outcroppings on the steep, barren, south slopes at the base of Grandview Canyon, whereas none was found on the juniper-clad benches. This woodrat built no nests in rocky areas; however, in the Joshua tree belt _N. l. lepida_ often built small nests at the bases of large standing or prostrate Joshua trees. There sticks from creosote bushes, along with cow dung and small stones were favorite building materials. Judging from the large number of unused woodrat nests in the Joshua tree flats it seemed that this rat was formerly far more common than it was in the period of this study. _Specimens examined._--Total, 9, distributed as follows: Los Angeles County: 6 mi. E and 1 mi. S Llano, 3500 ft., 4; Mescal Wash, 4200 ft., 5 (3PC). =Neotoma fuscipes macrotis= Thomas Dusky-footed Woodrat This subspecies was widely distributed along the coastal slope of the mountains from the coastal sage belt, at roughly 1600 feet, up to 6500 feet at the lower edge of the yellow pine forest and was most common in the chaparral association. In the coastal sage belt these woodrats are restricted to wash areas where large chaparral plants such as lemonadeberry and laurel sumac are used as nesting sites. In San Antonio Wash the occasional large juniper trees almost invariably harbor the nests of _fuscipes_. The general absence of suitable nesting sites in the sage belt probably limits the spread of _fuscipes_ in this area. In the upper part of the chaparral belt in talus these woodrats live beneath the angular boulders and build no visible houses. Several areas of talus occupied by woodrats were examined carefully and no sign of houses was noted. Two juveniles were found in the stomach of a rattlesnake (_Crotalus viridis helleri_) killed in May, 1948, at the mouth of Evey Canyon. Remains of woodrats were found in feces of the coyote and gray fox. Lactating females of this species were taken on March 16, and October 2, 1951. _Specimens examined._--Total, 4, distributed as follows: San Bernardino County: Icehouse Canyon, 5500 ft., 2. Los Angeles County: San Antonio Canyon, 2800 ft., 2. =Neotoma fuscipes simplex= True Dusky-footed Woodrat These rats were recorded from the yellow pine forests on Blue Ridge, at 8100 feet, down to the lower edge of the juniper belt, at 3800 feet. Their presence there as elsewhere was determined by the occurrence of adequate cover. On Blue Ridge they were taken in and near patches of snowbrush, currant, and choke cherry, and one was taken beneath a pile of logs where no nest was in evidence.