1922] Kellogg: California n Forms of Microtus Monimius 259 



Microtus montanus montanus (Peale) 



Peale Meadow Mouse 



Arvioola montana Peale (1848, pp. 44-45). 



Arvicola montana, Baird (1857, pp. 528, 741) ; and of authors. 



Arvicola longirostris Baird (1857, p. 531) ; and of authors. 



Arvicola (Myonomes) ripari'u.s, Coues (1874, p. 189), part; and of some 



authors. 

 Microtus longirostris, Trouessart (1897, p. 564). 

 Microtus montanus, Merriam (1899, p. 95). 



Microtus montanus, Bailey (1900, p. 27) ; and of some authors, part. 

 Microtus montanus montanus, Miller (1912, p. 216), part; and of some 



authors. 



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

 headwaters of Sacramento River, near Mount Shasta [probably close 

 to Sisson, 3600 feet altitude, Siskiyou County] , California ; October 4, 

 1841; collected by Titian R. Peale. (Type specimen cannot now be 

 found.) 



Range. — Siskiyou region of northern California, from Siskiyou 

 Mountains east to Tule Lake, and south to Fort Crook and Dana, 

 Shasta County. Vertical range from 2700 feet up to 6500 feet ; zonal 

 range Transition to Canadian. (See map, fig. Y.) 



Total number of specimens examined, 60, from the following local- 

 ities in California. Siskiyou County: Stud Horse Caiion, Siskiyou 

 Mts. (6500 feet), 1 (coll. Biol. Surv.) ; Brownell (4300 feet), 5 (coll. 

 Biol. Surv.) ; Mayten or Big Spring (2700 feet), 1 (Mus. Vert. Zool.) ; 

 Sisson (3600 feet), 32 (coll. Biol. Surv., 16; coll. A. B. Howell, 13; 

 Mus. Vert. Zool., 3). Shasta County : Dana, 2 (coll. Biol. Surv.) ; Fort 

 Crook (3000 feet), 17 (coll. Biol. Surv.). Modoc County: Carr's 

 Ranch, Rhett [Tule] Lake, 2 (coll. Biol, Surv.). 



Diagnosis. — Size large (hind foot 21 to 23 mm., condylobasal length 

 of skull in largest individuals, 28.3 mm.) ; skull relatively large (ratio 

 of zygomatic breadth to condylobasal length about 56 per cent), 

 and ridged in old adults; incisive foramina narrow and constricted 

 posteriorly ; bullae large and rounded ; pelage long, usually dark ; ears 

 very hair}-, relatively large, and not concealed by fur; hip glands 

 conspicuous in old adults. 



Measurements. — Average of 27 specimens from Sisson, California : 

 total length, 165.5 mm. (142-192) ; tail vertebrae, 48.44 mm. (41- 

 55) ; hind foot, 21.55 mm. (20-23) ; condylobasal length, 26.86 mm. 

 (24.9-28.3) ; occipito-nasal length, 26.29 mm. (25.2-28) ; basilar length, 

 Hensel, 24.31 mm. (22.5-26) ; nasal length, 7.55 mm. (6.8-8.2) ; zygo- 

 matic width, 15.45 mm. (14.2-16.9) ; interorbital constriction, 3.6 mm. 

 (3.4-4) ; interparietal width, 8.27 mm. (7.6-8.8) ; shelf of bony palate, 

 14.21 mm. (12.8-14.9); height cranium at bullae, 10.21 mm. (9.6- 

 10.7) ; mastoid width, 12.25 mm. (11.6-12.9) ; length upper molar 

 series, 6.61 mm. (6.2-7.3); length mandible, 17.34 mm. (16.4-18.9). 



