438 University of California Publications in Zoology — | Vou. 17 
Palaeontology, in which are contained some of the most interesting 
and important specimens known bearing upon the history of the 
Aplodontiidae and the apparently related fossil family Mylagaulidae. 
Acknowledgments are due the following persons: For the loan of 
additional material for study, to Messrs. F. J. V. Skiff and Wilfred 
H. Osgood, of the Field Museum of Natural History, Dr. John F. 
Bovard and Mr. Alfred C. Shelton, of the University of Oregon 
Museum, and Messrs. Samuel Henshaw and Outram Bangs, of the 
Museum of Comparative Zoology; for the courtesy of access to the 
collection under his charge, to Mr. Gerrit S. Miller, Jr., of the United 
States National Museum; for helpful suggestions regarding the his- 
torical problems involved, to Dr. John C. Merriam, of the University 
of California; for various suggestions in connection with the work, 
to Messrs. E. W. Nelson, T. S. Palmer, Vernon Bailey, Edward A. 
Preble, and Hartley H. T. Jackson, of the Biological Survey, and to 
Messrs. Gerrit S. Miller, Jr., and J. W. Gidley, of the United States 
National Museum; for a list of vernacular names of Aplodontia used 
by California Indians, to Dr. C. Hart Merriam, of the Harriman 
Foundation, Smithsonian Institution; and for eritical oversight, to 
Dr. Joseph Grinnell, of the Museum of Vertebrate Zoology, University 
of California, at whose instance the work was undertaken. 
3. MretrHops or MEASUREMENT 
All measurements are in millimeters. 
Cranial measurements, except where otherwise specified, are taken 
as follows: 
Basilar length: inferior lp of foramen magnum to posterior 
margin alveolus of incisor. 
Length of nasals: most anterior point on nasal bones to most 
posterior point. 
Width of nasals: greatest distance across both of them. 
Length of audital tube: outer border of foramen ovale to farthest 
lateral point (with reference to the skull) on zygomatic (or anterior) 
side of audital tube. 
Length of incisive foramina: greatest length of foramen on right 
side, that is, with skull resting on its dorsal surface and rostrum point- 
ing away from the observer. 
Zygomatic width: greatest inclusive measurement, taken outside 
of the zygomatic arches. 
