THE GROUND SQUIRRELS OF CALIFORNIA. 599 



to the present accomplisliment. A total of 1263 study skins of ground 

 squirrels taken within this state have been examined in the course of 

 our work. 



In the spring and summer of 1911, two field assistants from the 

 United States Public Health and Marine-Hospital Service were assigned 

 by Dr. Eupert Blue, then Surgeon in Command, San Francisco, to 

 accompany the Museum party working in south-central California, for 

 the purpose of increasing the common knowledge of the distribution 

 and manner of occurrence of the rodents of the region. Acknowledg- 

 ment is here made for the use of certain facts from the manuscript 

 report of that year's work made to Dr. Blue by the Director of the 

 Museum. 



During the past year, Dr. W. C. Billings, Surgeon, in temporary 

 charge, United States Public Health Service, San Francisco, has very 

 greatly aided us in having his field men send us specimens of ground 

 squirrels, both alive and dead, for experimentation and study. 



To Professor Harvey M. Hall, of the University of California, we 

 are indebted for identifying numerous seeds obtained from the cheek- 

 pouches of ground squirrels. 



Through special provision of the State Commissioner of Horticulture 

 we have been fortunate in being able to have the accompanying five 

 colored plates of ground squirrels drawn by the eminent animal artist, 

 Mr. Louis Agassiz Fuertes. We thank Mr. Fuertes for the special 

 pains he has taken in executing these drawings. 



Color terms used in our descriptions are taken from Ridgway's 

 Color Standards and Color Nomenclature (1912). 



Information used by us from published sources is credited through 

 the system of author, year and page references to the list of ' ' Literature 

 Cited" which appears at the end of this paper. The authority for 

 important information obtained from field notebooks or from letters is 

 given in parenthesis together with the abbreviation for the word 

 manuscript— "MS." 



Joseph Grinnell. 

 Joseph Dixon. 



September 13, 1918. 



