108 CALIFORNIA MAMMALS. 



tail blackish above, dull white below, sometimes tipped with 

 white. Young: plumbeous above, blackish at a later stage, with 

 but little ochraceous tinge on the sides; below ashy or grayish 

 white; tail scarcely lighter beneath. 



Length about 250 mm. (9-85 inches) ; tail vertebrae 140 

 (5.50) ; hind foot 26 (1.03) ; ear from crown 23 (.90). 



Type locality. Monterey. California. 



The California Mouse is found in the chemisal and in un- 

 derbrush in open forests, in the valleys, foothills and lower moun- 

 tains of the coast region of California from some distance north 

 of San Francisco south to about Santa Barbara where it blends 

 into the next subspecies. It appears to reach the lower part of 

 the Sierra Nevada in small numbers. 



For some time after its discovery naturalists supposed that 

 ihi': species lived in the nests of the Brush Rats and were in some 

 manner parasitic on them, but it is now known to occur in brush 

 in general and to have habits similar to those of other wa?d 

 mice. 



Peromyscus calif or nicus insignis Rhoads. (Distin- 

 guished by a mark. ) 



CHEMISAL MOUSE. 



Very similar to calif ornicus; slightly smaller in avei-ige; 

 lighter colored, back with less black, sides less ochraceous. 



Length about 233 mm. (9.85 inches) ; tail vertebrcT 130 

 (5.10) ; hind foot 25 (i) ; ear from crown 22 (.86). 



l*ype locality, Dulzura, San Diego County, California. 



The Chemisal ]Mouse occurs in northwestern Lower Calif- 

 ornia and in southern California from the sea coast to the lower 

 edge of the pines. They do not frequent open valleys, but are 

 more or less common in the cliemisal and in the brush among 

 the oaks. They frequently inhabit knotholes and hollows in 

 leaning trees, being fair climbers. They are fond of running on 

 logs. I do not find them more common about Brush Rat nests 



