vi PREFACE 



an 'open sesame' to the treasures he desired to see, and everything was 

 done to forward his investigations and make his visit profitable as 

 well as agreeable. 



Among the large number therefore to whom the Author feels 

 especially indebted beginning in his own land, he would first mention 

 his distinguished friend, Professor Henry Fairfield Osborn, LL.D., 

 D.Sc, Sc.D., etc., President of the American Museum of Natural 

 History, who from the beginning has taken a deep interest in this 

 work, and through whose efforts solely its publication in the present 

 attractive form has been made possible. The Author desires there- 

 fore to express his lively appreciation of a scientific colleague's aid 

 in making accessible to mammalogists throughout the world a contri- 

 bution, the result of much weary labor, towards the elucidation of the 

 members of the most important Order in the Animal Kingdom. 



To Dr. J. A. Allen, Curator of Mammalogy and Ornithology, and 

 Dr. W. K. Gregory, Assistant in Vertebrate Paleontology in the 

 American Museum of Natural History, New York, the Author is 

 indebted ; especially to Dr. W. K. Gregory who gave the most careful 

 supervision to the publication of the work, as well as to the illustra- 

 tions that so much enhance the value of the volumes, a labor that was 

 by no means slight nor free from various difficulties. To Witmer 

 Stone, Esq., Curator of Ornithology in the Philadelphia Academy of 

 Natural Sciences ; to G. S. Miller, Esq., Assistant Curator Department 

 of Mammals, and N. Hollister, Esq., Assistant in the same Department 

 of the United States National Museum the Author is under many obli- 

 gations. And finally his thanks are due to F. J. V. Skiff, Esq., Director 

 of the Field Museum of Natural History, Chicago, for the loan of 

 skulls from that Institution. 



In England he would express his great obligation to Oldfield 

 Thomas, Esq., Head of the Department of Mammals in the British 

 Museum, where the collection of the Primates, regarding it in a general 

 sense, is probably the finest and most complete in the world, the Author 

 was permitted to work as if it were his personal property, Mr. Thomas 

 only insisting that all novelties discovered should be described by the 

 Author, and not as would naturally be expected, by the Head of the 

 Department. Also to Guy Dollman, Esq., Assistant in Mammalogy 

 in the same Institution, who aided the writer in many ways, and 

 whose intimate knowledge of the collection and especially the location 

 of the specimens by which much time was saved, was of the greatest 

 advantage. Also to R. Lydekker, Esq., who permitted the removal 

 from the cases of many mounted specimens, all of which were in his 



