1918] Kellogg: Microtus californicus Group of Meadow Mice 5 



Microtus californicus californicus (Peale) 

 West-central California Meadow Mouse 



Arvicola calif ornica Peale (1848, p. 46, pi. 11, fig. 2). San Francisco Bay. 



Arvicola edax Le Conte (1853, p. 405). California (south of San Fran- 

 cisco, fide Baird, 1857, p. 532). 



Arvicola troiviridgii Baird (1857, pp. 529-530). Monterey. Original de- 

 scription under Ai'vicoJa montana. 



Arvicola {Myonomes) riparvus, Coues and Yarrow (1875, pp. 106, 107); 

 and other authors, part. 



(Microtus) montanus, Trouessart (1898-1899, p. 563). 



Microtus californicus, of authors, part. 



Microtus edax, of some authors, part. 



Type specimen. — Sex unknown; no. " U. S. Nat. Mus. ; 



vicinity of San Francisco Bay [probably San Francisquito Creek, 

 near Palo Alto], California; [October 26, 1841] ; collected by Titian 

 R. Peale. 



Range. — Coastal region of west-central California, west of San 

 Joaquin Valley, from Pozo, San Luis Obispo County, north to San 

 Francisco, and to Walnut Creek, Contra Costa County. Vertical 

 range from sea level up at least to 2800 feet ; zonal range Upper 

 Sonoran and Transition. (See map.) 



Total number of specimens examined, 93, from the following 

 localities in California. Contra Costa County : Walnut Creek, 13 ; 

 west side Mount Diablo, 2. Alameda County: Berkeley, 24; Pied- 

 mont, 6 ; Melrose Marsh, 9 ; Elmhurst, 1 ; Alvarado, 1. San Mateo 

 County : Redwood City, 9 ; Menlo Park, 1 ; Pescadero, 3. Santa Clara 

 County : Black Mountain, 2 ; Palo Alto, 8 ; Stanford University, 1. 

 Monterey County: Monterey, 6; Salinas Valley, 1. Merced County: 

 Sweeney's Ranch, 22 miles south of Los Baiios, 6. 



Diagnosis. — Size medium (hind foot, 20 to 23 mm., condylobasal 

 length of skull in largest individuals, 30.4 mm.) ; second upper molar 

 wathout posterior internal loop or lobe ; skull rather broad, angular, 

 and with well developed ridges in adults (ratio of zygomatic breadth 

 to condylobasal length about 53%) ; old adults tending to show a 

 median interorbital ridge ; incisive foramina wide open ; pelage coarse 

 and harsh ; ears large, conspicuous above fur ; hip glands present in 

 adult males. 



Color. — Mass effect of dorsal area ranging from light Brussels 

 brown to Saccardo's umber, with varying suffusion or admixture of 

 long dark overhairs, and strongly tinged with buffy along sides and 

 on neck. In fresh pelage : Hairs of upperparts blackish plumbeous 

 basally, with light tipped portion grading from an indefinite ochra- 

 ceous-tawny to cinnamon buff, the long overhairs varying from Mars 

 brown to aniline black ; sides lighter and with fewer long overhairs 

 than upperparts ; rump normally no brighter than rest of upperparts. 

 Underparts pallid neutral gray, dulled by the plumbeous bases of 

 hairs ; anal area whitish. Terminal portions of whiskers whitish, or 

 else hairs nearly unicolor, in w'hich case they are almost the same color 

 as long overhairs of upperparts. Nose may or may not be darker 

 than area in front of eyes. Ears large, with anterior border densely 



