CONTENTS. 



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 



If. 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 

 <?. The Line of the Aves : . 123 



/. The Line of the Mammalia . . . . iz6 



g. Review of the Phylogeny of the Mammalia 138 



