CONTENTS 



PAGl 



INTRODUCTION, 



CLASSIFICATION OF THE MAMMALIA ADOPTED IN THIS BOOK, n 



CHAPTER I. 



THE TRANSITION FROM THE REPTILIAN TO THE MOST PRIMITIVE 

 MAMMALIAN TEETH. 



1. The Upper Triassic Mammals Dromatherinm and Microconodon, - 18 



2. A new classification of the Mesozoic Mammals, - 21 



3. Illustrations of the chief Triconodonta and Trituberculata, 24 



4. The origin of the tritubercular type sought in 1888 among the 



Mesozoic Mammalia, 31 



CHAPTER II. 



FIRST OUTLINE OF TRITUBERCULAR EVOLUTION IN MAMMALS, 36 



CHAPTER III. 



TRITUBERCULY IN RELATION TO THE HUMAN MOLAR TEETH AND 

 THE PRIMATES. 



1. Ontogenetic development of the teeth, 48 



2. "The history of the cusps of the human molar teeth," p. 55. The 



concrescence theory, p. 57. Mechanical relations of the upper 

 and lower teeth, p. 60. Evidence that the upper human molars 

 were triangular, p. 62 



