viii AMERICAN MESOZOIC MAMMALIA 



important material in his care and permitted its inclusion in this study — an action the 

 more liberal and disinterested in that he had himself performed the laborious task of 

 preparing these specimens for study and had planned eventually to monograph them. 

 The authorities of the United States National Museum also provided numerous photo- 

 graphs for study and publication. Mr. O. A. Peterson brought to New^ York for the 

 author's study the whole of the Lance mammal collection in the Carnegie Museum. 

 Professor W. J. Sinclair permitted examination of the Lance mammals in the Geologi- 

 cal Museum of Princeton University. The rich Mesozoic mammal collections of the 

 American Museum of Natural History were placed freely in the author's hands, both 

 before and since his official connection with that institution. Professor Henry Fairfield 

 Osborn, Dr. W. D. Matthew, and Dr. W. K. Gregory have all taken a constant and 

 helpful interest in the work. Many other friends and colleagues have placed the author 

 in their debt in ways more difficult of formal acknowledgment. 



Unless otherwise credited, the drawings were made by Rudolph Weber and Mrs. 

 Louise Nash and the photographs by the author. 



The manuscript was complete in its present form on May i, 1928, but in some 

 cases it has been possible to take cognizance of work published since that date. 



G. G. S. 



New York, 



December ij, ipsS. 



