CONTENTS 



PAGE 



PREFACE . . . . . . 5 



INTRODUCTION 



1. Societies and organisms. 2. Individuals, colonies and 

 societies. 3. Communities and societies. 4. Distinc- 

 tive characters of societies of which the members are 

 united by social contract . . . . 7 



BOOK I 



UNIVERSALITY OF DEGENERATIVE EVOLUTION 



PART I. Degeneration in the development of institutions 



and organs . . . . .. 21 



Chapter I. In the evolution of organs all modification is 



necessarily attended by degeneration ... 22 

 1. Preliminary considerations . . . 



(1) Original formation of organs in ancestral forms . 23 



(2) Development of organs in the individual . . 23 



(3) Philogenetic evolution of function . . 25 



(4) Individual adaptation . . . . 26 

 Section I. Transformation of organs of animals . 30 



2. Transformation of homodynamic organs in the indivi- 

 dual (metameric appendages) ... 30 

 The cray-fish ...... 31 



3. Transformation of homologous organs in individuals 



of different species (limbs) .... 41 



Limbs adapted to an aquatic life (Ceratodus, Ortha- 

 canthus, Protoptems amphibius, Protopterus annec- 

 tens, Lepidosiren . . . . . 43 



Limbs adapted to a terrestrial life . - . . 43 



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