226 University of California Publications in Zoology  [Vou.17 
ford Junior University; to Dr. Barton W. Evermann and Mr. John 
Rowley of the California Academy of Sciences; to Professor Charles 
A. Kofoid of the University of California; to Dr. Leonard Stejneger, 
Mr. Gerrit S. Miller, Jr., and Mr. Ned Hollister of the United States 
National Museum; to Mr. Henry W. Henshaw, Mr. E. W. Nelson and 
Mr. Arthur H. Howell of the United States Bureau of Biological 
Survey; to Dr. Witmer Stone of the Academy of Natural Sciences 
of Philadelphia; to Dr. J. A. Allen of the American Museum of 
Natural History, New York; to Dr. Glover M. Allen of the Museum 
of Comparative Zoology, Cambridge; and to Mr. Perey A. Taverner, 
of the Museum of the Canadian Geological Survey, Ottawa. To Dr. 
Joseph Grinnell of the California Museum of Vertebrate Zoology 
the writer is indebted not only for permission to make full use of 
the collections and field notes under his charge, but also for encourage- 
ment and frequent help given during the five years in which this 
paper has been in preparation. 
A preliminary manuscript, the first draft of the present paper, 
was prepared when the writer was a graduate student in the Depart- 
ment of Zoology of the University of California, m 1912-13; during 
that year much kindly criticism was received from Professor Charles 
A. Kofoid, head of the department. 
To Mr. Charles L. Camp, Mr. Wilson C. Hanna, Miss Grace Swerd- 
feger, Miss Winifred N. Wear, and Messrs. Eldon, Adrey, and Raleigh 
Borell, the writer is under obligation for contributions of living speci- 
mens of bats. 
Mr. Frank Stephens has generously permitted the use of notes 
gathered during many years of field study of California mammals. 
Finally, the author is deeply indebted to the entire staff of the 
California Museum of Vertebrate Zoology for aid given in many ways. 
The facilities afforded in this institution for this special study have 
been indispensable. 
MaTERIAL 
The Californian material studied, and upon which this paper is 
based, consists of some 1500 specimens, from the following sources: 
942 specimens from the Museum of Vertebrate Zoology; 218 from 
the collections of Leland Stanford Junior University; 107 from the 
United States National Museum; 88 from the collection of the United 
States Bureau of Biological Survey; 34 from the collection of the 
