viii CONTENTS 



Explanation of Plate III 4* 



Oahu the Metropolis of the Achatinellidae 4 2 



Plate A. Map of the Hawaiian Islands. 



Plate I. Eight Genera of Achatinellidae. 



Plate B. Map of Oahu, Hawaiian Islands. 



Plate II. Twenty-five Species of Achatinella. 



Plate III. Variation and Intergrading of Buliinella. 



Explanation of Plate B 43 



CHAPTER V. THE FOUR SEGREGATIVE PRINCIPLES. 



Racial and Habit udinal Segregation 45~5 



Interaction of Acquired and Inherited Characters 45 



Segregation a Fundamental Law 47 



Segregate Association 48 



Interaction of Racial and Social Factors 49 



Determinate Evolution of Evolutionary Terminology 50 



Segregation the Combined Result from Four Principles 5 '-5 5 



Racial Segregation Controlled by Two Principles and Habitudinal 



Segregation by Two 51 



Importance of Isolation 51 



Definitions of the Four Segregative Principles 53 



Objections to the Terms. 54 



Interaction of the Four Principles 55-7 



Repeated Action of One or Combined Action of Several Principles . . 55 



Importance of Each of the Principles 56 



Two Methods of Generalization 58 



Change of Tradition in Chimney Swift 59 



Variation and Accommodation Two Methods of Adjustment 59 



Conditions Suddenly or Gradually Encountered 60 



Accommodation in Man 61 



Endonomic Selection 63 



Coincident Selection 64 



Endonomic and Coincident Selection Contrasted 65 



Coincident Selection Illustrated 66 



Endonomic and Coincident Influences Defined 66 



A Colony of Cats with Aquatic Habits 67 



Structural Isolation and Structural Selection Illustrated 68-70 



Young Snails with Reverse Coil from that of Parents 70 



Mutations and Varieties 71 



Theories Compared 72 



Degeneration with Cessation of Selection 73 



Degeneration in Eye-sight and its Lessons 74 



Degeneration in Breeding Instincts 75~?6 



Mutation as Recently Expounded by De Vries 77 



Selection and Inheritance of Acquired Characters 78 



CHAPTER VI. -ANALYSIS OF THE FOUR PRINCIPLES OF SEGREGATION. 



Chief Divisions of the Four Principles 79~Si 



Six Conditions on which Racial Evolution Rests 79 



Six Conditions on which Habitudinal Evolution Rests 80 



