PREFACE 13 



tryman Bergson has first applied the newer and grander bio- 

 logical interpretation to the philosophy of life. 



The author recognizes that a Dental Anatomy course of 

 today calls for the description mainly of living types which, 

 however, can only be properly presented by constant reference 

 to ancestral forms. Hence, although the following pages deal 

 mainly with recent dentitions, the paleontological viewpoint has 

 been adopted wherever it has been possible to do this without 

 overburdening the text, To have elaborated more upon the 

 paleontological aspect would have greatly increased the size of 

 the volume and made it more than a simple introduction to the 

 study of teeth. 



In the preparation of this manuscript the author is indebted 

 to many investigators who by personal contact or by their writ- 

 ings have influenced his thought. It is not possible to mention 

 all by name, nor has it been thought advisable in so elementary 

 a book to include a literature index.* To the late Professor 

 A. H. Young, to Professor Grafton Elliot Smith and to Pro- 

 fessor Arthur Keith I owe that debt of gratitude which can be 

 acknowledged but never paid for my training in comparative 

 anatomy. To Professor H. F. Osborn, Dr. W. D. Matthew and 

 Dr. W. K. Gregory whose work has so greatly influenced me 

 and upon whose writings I have so largely drawn I am happy 

 also to declare my indebtedness. To Professor B. A. Bensley's 

 work I owe the conception of the fundamental plan of this 

 volume. For recent encouragement and the material resources 

 with which the Anatomical Laboratory here is so richly provided 

 I am under obligation to four gentlemen. Dr. Hamann my pred- 

 ecessor and colleague has spared no effort to acquire what- 

 ever has been necessary to equip the Museum with every ad- 

 vantage for the work. Mr. G. G. Marshall has provided us 

 with a large collection of Ohio Mammals. The Hon. Newton D. 

 Baker when Mayor of Cleveland and his indefatigible Com- 



*A few selected references to recent literature upon the subject of teeth and allied 

 problems mentioned in this volume are presented as an appendix upon page 282. This 

 list is merely intended to refer the student who desires a wider acquaintance with 

 the subject to certain original articles from which he will be able to obtain a more 

 comprehensive view and an introduction to the literature. 



