====================================================== | Number | Per cent | | of total -----------------------------------+--------+--------- Dipodomys panamintinus mohavensis | 36 | 59.0 Dipodomys merriami merriami | 15 | 24.6 Onychomys torridus pulcher | 4 | 6.6 Peromyscus maniculatus gambeli | 6 | 9.8 -----------------------------------+--------+--------- Populations of _Dipodomys merriami_ and _D. panamintinus_ fluctuate widely, possibly in response to weather cycles. In November of 1948 trapping in the Joshua belt showed that _panamintinus_ outnumbered _merriami_ approximately three to one, whereas in December of 1951, after a succession of unusually dry years, _merriami_ was the more numerous. Further, _merriami_ occurred in the lower parts of the juniper belt in 1951 where in 1948 it seemed to be absent. _Dipodomys merriami merriami_ and _Onychomys torridus pulcher_ are diagnostic of the Joshua tree woodland association in the San Gabriel Mountains area, since few individuals of either species occur outside of this association. ACCOUNTS OF SPECIES Family DIDELPHIDAE =Didelphis marsupialis virginiana= Kerr Virginia Opossum The opossum is common in and near small towns and cultivated areas at the Pacific base of the mountain range and does not thrive away from human habitation; extensive trapping in the coastal sage and chaparral belts produced no specimens except immediately adjacent to citrus groves. Pequegnat (1951:47) mentions that opossums in the Santa Ana Mountains of southern California are in the lower parts of the larger canyons, especially near human habitation. _Specimens examined._--Los Angeles County: Claremont, 1600 ft., 2 (PC). Family TALPIDAE =Scapanus latimanus occultus= Grinnell and Swarth California Mole Workings of moles were found on the Pacific slope of the mountains from 1600 feet at Claremont up to 7500 feet on Blue Ridge, and on the Pacific slope beneath basin sagebrush in Cajon Canyon one mile from desert slope Joshua-tree flats, but not on the desert slope, although moles probably occur on that slope in some of the places where there is suitable habitat. Near Camp Baldy in the sandy soil beneath groves of alders moles seemed to be especially abundant. Although common on the coastal face of the range, moles shunned compact, dry, or rocky soils. In the greasewood chaparral one-half mile west of the mouth of Palmer Canyon, where the soil was hard and rocky, mole tunnels were in soft soil that had accumulated at the edge of a fire road beneath a steep road cut. The assumption is that this accumulation contained insects attractive, as food, to the moles. _Specimens examined_, 2: Los Angeles County: Camp Baldy, 4200 ft., 1(PC); Claremont, 1600 ft., 1(PC). Family SORICIDAE =Sorex obscurus parvidens= Jackson Dusky Shrew