VI 



CONTENTS 



Section XIV. 



XV. 



XVI. 



XVII. 



XVIII. 



XIX. 



XX. 



XXI. 



XXII. 

 XXIII. 



XXIV. 

 XXV. 



XXVI. 

 XXVII. 



XXVIII. 



XXIX. 



XXX. 

 XXXI. 



XXXII. 



Relations between the Size of Animals and the Me- 

 diums in Which They Live 



Permanency of Specific Peculiarities in All Organized 

 Beings 



Relations between Animals and Plants and the Sur- 

 rounding World 



Relations of Individuals to One Another 

 Metamorphoses of Animals 

 Duration of Life 

 Alternate Generations 



Succession of Animals and Plants in Geological 

 Times 



Localization of Types in Past Ages 

 Limitation of Species to Particular Geological Pe- 

 riods 



Parallelism between the Geological Succession of 

 Animals and Plants and Their Present Relative 

 Standing 



Parallelism between the Geological Succession of 

 Animals and the Embryonic Growth of Their Living 

 Representatives 



Prophetic Types among Animals 

 Parallelism between the Structural Gradation of Ani- 

 mals and Their Embryonic Growth 

 Relations between the Structure, the Embryonic 

 Growth, the Geological Succession, and the Geo- 

 graphical Distribution of Animals 

 Mutual Dependence of the Animal and Vegetable 

 Kingdoms 



Parasitic Animals and Plants 



Combinations in Time and Space of Various Kinds 

 of Relations among Animals 

 Recapitulation 



56 



58 



65 

 72 

 76 

 89 

 91 



94 

 99 



101 



104 



110 

 115 



117 



119 



122 

 123 



127 

 132 



CHAPTER II. LEADING GROUPS OF THE EXISTING SYS- 

 TEMS OF ANIMALS 



Section I. Great Types or Branches of the Animal Kingdom 139 



II. Classes of Animals 148 



III. Orders among Animals 155 



IV. Families 161 



