1918] Kellogg: Microt us calif ornicus Group of Meadow Mice 21 



phery over base of incisor marked by obvious protuberance. Base 

 of mandibular foramen considerably above level of cutting surface of 

 last lower molar. Mental foramen on lateral face situated somewhat 

 below superior surface of diastema. 



Teeth. — Molariform series essentially as in calif ornicus, but with 

 relatively narrower transverse loops. Anterior loop of M- crescentic 

 though small. An internal lobe may or may not be present on poste- 

 rior triangle of M=. The enamel folding of M- may frequently be of 

 a more complicated type than that in aestuarinus. In this case the 

 inner limb of the long terminal loop is isolated as a definite second 

 inner closed triangle. 



Mj and M2 similar to those of calif ornicus, but M3 may have the 

 second loop constricted in the middle to form two closed triangles. 

 Transverse loops very wide. 



Remarks. — It is strange that such a well marked race of the cali- 

 f ornicus group could have been overlooked for so long a time. Mari- 

 posae is an inhabitant mainly of the Sierran foothills, extending down 

 along the rivers and streams to meet the range of aestuarinus. Speci- 

 mens from Minkler and Clovis exhibit some of the characters of 

 aestuarinus, but in the main approach mariposae more closely. In 

 some respects these specimens are also intermediate between aestua- 

 rinus and vallicola. Bailey (1900, p. 35) mentions the fact that the 

 effect of red soil is noticeable in specimens of Microtus californicus 

 from the vicinity of Auburn. Other specimens of this form, mari- 

 posae, which is characterized by reddish color, were closely scrutinized 

 to make sure that the coloration was real and not adventitious. No 

 indication of red soil could be found in the specimens examined. 



Microtus californicus vallicola Bailey 

 Owens Valley Meadow Mouse 



Microtus californicus vallicola Bailey (1S98, p. 89). Lone Pine, Inyo 



County. 

 Microtus californicus vallicola, of authors, part. 



25393 . ri 



Type specimen. — Female adult ; no. w^;^ , Biol. Surv. Coll., U. S. 



Nat. Mus. ; Lone Pine, 3700 feet altitude, Inyo County, California; 

 December 23, 1890; collected by E. W. Nelson; original no. 149. 



Range. — Owens Valley region of California, east of Sierra Nevada, 

 from Olancha, Inyo County, north to Benton, Mono County; east to 

 head of Willow Creek in north end of Panamint Mountains {fide 

 Bailey, loc. cit.). Vertical range from 3700 feet up at least to 5400 

 feet ; zonal range Lower and Upper Sonoran. (See map.) 



Total number of specimens examined, 96, from the following locali- 

 ties in California. Inyo County : Lone Pine Creek near Lone Pine, 



