498 BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



Color. — Adults in July: Upper parts light brown without any distinct Vjlack; belly buffy 

 brown; throat gray, inclosing a sharp, dusky chin stripe; a small spot over each nostril 

 whitish. 



Skull. — Small and narrow; nasals short and rounded or pointed at posterior end, never 

 notched; incisive foramina widest at posterior end; incisors heavy, molars light. 



Measurements. — Type: Total length, 470; tail, 202; hind foot, 67. Average of 6 adults:, 

 463, 204, 68. Skull of type: basal length, 55; nasals, IS; zygomatic breadth, 35; mastoid 

 breadth 25; alveolar length of upper molar series, 15. 



Remarks. — This form is distinguished from zibethicus by paler color, smaller size, heavier 

 incisors, unnotched nasals, and form of incisive foramina; from pallidus by darker color, 

 narrower skull, form of nasals and incisive foramina, and slightly heavier dentition. No 

 other comparisons are necessar}-. (Proc. Biol. Soc. Washington, XV, 1902, p. 119.) 



Genus MICROTUS Schrank (1798). 



Microtus Schrank, Fauna Boica, I, Pt. 1, 1798, p. 72. — Lataste, Le Naturaliste, II, 

 1883, p. 348.— Miller, North American Fauna, No. 12, July 23, 1896, p. 44 

 (Genera and Subgenera of Voles and Lemmings). 



Arvicola Lacepede, Mem. de ITnstitut, III, 1801, p. 489. 



Dentition.— I.}E\; U.lzl =^ 16. 



Trjpe. — 2Ius terrestris Linnaeus. 



Upper incisors without grooves ; lower incisors with roots on outer 

 side of molar series ; molars rootless ; enamel pattern characterized 

 by approximate equality of re-entrant angles; nii usually with 5 

 closed or nearly closed triangles; M^ with 1, 2, or 3 closed triangles; 

 tail nearly always longer than hind foot, terete; feet,, fur, eyes, and 

 ears very variable ; thumb never with a well-deA^eloped ligulate nail. 

 {G. S. Miller, jr.) 



Subgenus MICROTUS Schrank (1798). 



Microtus Schrank, Fauna Boica, i, Pt. 1, 1798, p. 72. — Miller, N. Am. Fauna, No. 12 

 July 23, 1896, p. 63 (subgenus). 



Palate normal; m^ without closed triangles; mi normally with 

 5 closed triangles and 9 salient angles; m^ normally with 3 closed 

 triangles and 7 or 8 salient angles; mammae, 8; plantar tubercles, 6; 

 soles moderately hairy; claws of hind feet longest; fur not specially 

 modified. (6^. S. Miller, jr.) 



MICROTUS CALIFORNICUS (Peale). 

 CALIFORNIA MEADOW-MOTJSE OR VOLE. 



Arvicola califomica Peale, U. S. Expl. Exped., VIII, Mam., 1848, p. 46 (original 

 description). 



Microtus ccUifomicus Teouessart, Catal. Mam., Pt. 3, 1897, p. 563. — Elliot, Field 

 Col. Mus., Zool. Ser., II, 1901 (Synop. Mam. N. Am.).— Bailey, North Ameri- 

 can Fauna, No. 17, June 6, 1900, p. 34, fig. 3 (teeth). — Miller and Rehn, Proc. 

 Bost. Soc. Nat. Hist., XXX, No. 1, Dec. 27, 1901, p. 120 (Syst. Results Study 

 N. Am. Mam. to close of 1900). 



