468 University of California Publications in Zoology [Vol. 12 



show a strong tendency to grade into xanthogenys, the form of the 

 California lowlands. 



The closest relatives of Mustela xanthogenys xanthogenys of Cali- 

 fornia west of the desert divides, from the Mexican line north through 

 the San Diegan district, and in west-central California east of north- 

 ern humid coast belt, at least to the head of the Sacramento Valley, 

 are Mustela xanthogenys munda (doubtfully recognizable), of the 

 humid coast Transition north of San Francisco Bay, and Mustela 

 xanthogenys oregonensis, of Rogue River Valley, Oregon. 



The Pacific Mink, Mustela vison energumenos, is most closely 

 related to its neighbors, Mustela vison nesolestes, of the Alexander 

 Archipelago, Alaska, and Mustela vison lacustris of the interior of 

 Canada and the northern United States (Hollister, 1913, p. 476). 



Turning to the genus Spilogale, it is noted that two closely related 

 forms invade eastern California but do not cross the Sierra Nevada. 

 These are Spilogale gracilis saxatilis, found in the northeastern corner 

 of the state, and Spilogale gracilis gracilis, inhabiting the Sonoran 

 zones of the Inyo region. Spilogale arizonae arizonae of the lower 

 Colorado River region is most closely allied to Spilogale arizonae 

 martirensis of Lower California. Spilogale phenax phenax, inhabit- 

 ing most of the Pacific slope of California, is apparently replaced by 

 Spilogale phenax latifrons in the coast region of extreme northern 

 California and Oregon. Another race of the species phenax, Spilo- 

 gale phenax olympica, is found on the Olympic Peninsula and the 

 shores of Puget Sound (Miller, 1912, p. 106). 



The genus Mephitis is represented by five forms within California, 

 three of these belonging to the species occidentalis. This species is 

 represented in western North America by five races (Howell, 1901, 

 pp. 34-38). Mephitis occidentalis occidentalis is found in northern 

 and central California, west of the Sierra-Cascade system, from Mon- 

 terey Bay to the Willamette Valley, Oregon. The coast region of 

 Washington and northern Oregon, as well as the shores of Puget 

 Sound, are occupied by Mephitis occidentalis spissigrada. In the 

 eastern part of southern Washington and northern Oregon, on the 

 desert side of the Cascade Mountains, is found Mephitis occidentalis 

 notata, which intergrades with occidentalis and major. Mephitis 

 occidentalis major is found in eastern Oregon, northeastern California 

 and Nevada, ranging east to the Wasatch range in Utah. Its closest 

 relatives are notata and occidentalis, its neighbors on the north and 

 west respectively. In southern California the group is represented by 





