UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



ZOOLOGY 



Vol. 21, No. 1, pp. 1-42, 1 figure in text December 28, 1918 



A REVISION OF THE MICROTUS CALIFOR- 

 NICUS GROUP OF MEADOW MICE 



BY 



EEMINGTON KELLOGG 



(Contribution from the Museum of Vertebrate Zoology of the University of California) 



INTRODUCTION 



The following revision of the races of the Microtus calif ornicus 

 group of meadow mice is based on a study of approximately seven 

 hundred and ninety specimens, these being from one hundred and 

 fourteen localities, all but one within the State of California. This 

 material has included the type specimens of Microtus californicus 

 huperuthrus, Microtus " edax" [=M. c. aestum-inus], and M. c. cali- 

 fornicus, as also topotype series of all the other previously described 

 forms. Microtus californicus in one or another of its geographic races 

 occurs in abundance throughout the greater part of California, and 

 also extends a little way into Oregon on the north and into Lower 

 California on the south. It is most commonly met with in the Upper 

 Sonoran and Transition life-zones, but in the southern portion of its 

 range extends up into the Boreal zone as well as down into the Lower 

 Sonoran zone. 



The Microtus californicus stock seems to have been extraordinarily 

 adaptable, as its descendants have come to occupy areas of the most 

 diverse conditions of environment, including atmospheric extremes of 

 both humidity and temperature. Most of the subspecies inhabit moist 

 or wet ground, and one of them, aestuarinus, may almost be considered 

 aquatic ; yet others, mariposae for example, live as a rule on dryish 

 hillsides. Two, scirpensis and moliavensis, live in regions of extremely 

 warm summers. One race, neglectus, has an anomalous distribution 

 in that it extends Avithin its own range uninterruptedly from the tidal 

 marshes of the seacoast to the Boreal zone of adjacent mountain tops. 



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