xxvi CONTENTS 



SECTION III 



PAGE 



INFLUENCE OF ADAPTATION IN THE FORMATION OF SPECIES 63 



Is everything adapted ? . . . . .63 



Death as an Adaptation . . . • .67 



Further Considerations on the Adaptation and Direction of 

 Evolution of the Markings of CaterpiHars. Absence of 

 Sexual Combination in this Evolution . . .72 



Characters which are inessential (indifferent) to the Life of the 



Organism . . . • • .74 



SECTION IV 



ACQUIRED CHARACTERS 78 



Methods of Investigation — The Period of Time to be claimed 



for Evolution . . . . .78 



Acquired Characters due to Direct External Action . . 87 



Experiments on the Influence of Temperature on Lej)idoptera . 116 



Further Remarks on the Causes which Change the General 



Colouring of Animals . . . . .135 



Influences of Locality on the Variation of Animals, and thereby 



on the Formation of Species . . . .139 



Importance of the Stimulation of the Nervous System in 



relation to Adaptation and the Origin of Species . 142 



Particular Facts which prove the Influence of Nutrition and 

 other external Conditions on tlie Variation and Formation 

 of Species in Lepidoptera . . . .149 



Characters acquired by Use . . . . .153 



Inheritance of Injuries and Diseases . . . ,173 



SECTION V 



DISUSE OF ORGANS DEGENERATION PAMMIXIS 205 



Pammixis . . . . . . .217 



