viii PREFACE, 



North America, as understood in this volume, extends from the 

 North Pole to the boundary dividing the United States and Mexico, 

 and it has not been attempted to give the range of any species south 

 of the Mexican line, although some do pass it, but to restrict the 

 description of geographical distribution to the limits mentioned, as 

 well as to the adjacent seas. Certain forms have been described 

 while the volume was passing through the press, too late for them to 

 appear in their proper position in the body of the book. These will 

 be found in the Appendix. 



And now I have much pleasure in acknowledging the assistance 

 received from various friends while engaged upon this work, and I 

 desire to express my thanks to Dr. J. A. Allen, Curator of Vertebrate 

 Zoologj' in the American Museum of Natural History, New York; to 

 Dr. C. H. Merriam, Chief of the Biological Survey, Department of 

 Agriculture, Washington; to Dr. F. \V. -True, Curator, and G. S. 

 Miller, Esq., Assistant Curator of Zoology, United States National 

 Museum, Washington, for the loan of skulls not contained in the 

 Field Columbian Museum. To Witmer Stone, Esq., Curator of 

 Zoology in the Academj' of Natural Sciences, Philadelphia; and Dr. 

 A. Woodward, Librarian, and I. N. Sniffen, Esq., Assistant Libra- 

 rian in the New York Museum of Natural History, I am much 

 indebted for information conveyed to me from the volumes in the 

 fine libraries of their respective institutions. The half-tones that 

 illustrate the volume exhibit, with but few exceptions, every genus 

 and subgenus of North American Mammal, and the collection to 

 which each cranium belongs, and its catalogue number, is stated in 

 every instance. D. G. E. 



3d Jan'y, 1901. 



