CONTENTS. 



PAGE 



PREFACE v 



TABLE OF CONTENTS ix 



LIST OF ILLUSTRATIONS xiii 



INTRODUCTION . i 



PART I. THE NATURE OF VARIATION. 



PRELIMINARY 19 



CHAPTER I. VARIATION. 



Preliminary 21 



1. Variations of Specific Characters 25 



a. Variations in Cicindela 25 



b. Variations in Osceola doliata 29 



c. Color- Variations in Cnemidophorus 41 



d. Variations in North American Birds and Mam- 



mals in Relation to Locality 45 



2. Variation of Structural Characters 58 



3. Successional Relation 62 



CHAPTER II. PHYLOGENY. 



1. General Phylogeny 74 



2. Phylogeny of the Vertebrata 83 



a. Phylogeny of the Classes 83 



b. The Line of the Pisces 99 



c. The Line of the Batrachia ....'... 108 



d. The Line of the Reptilia 113 



e. The Line of the Aves 123 



/. The Line of the Mammalia 126 



g. Review of the Phylogeny of the Mammalia . 138 



