CONTENTS xv 



SUPPLEMENTARY FACTORS OF EVOLUTION 



Page 



COURTSHIP SELECTION 489 



LAMARCKISM Acquired Characters; Use and Disuse; Influence of the Environ- 

 ment- - - - 489 



NEO-LAMARCKISM - 491 



VARIATION 



Kinds of Variation Discontinuous Variation. Adaptation to the Environment. 

 Somatic and Germinal Variation. Weismann's Views on the Non-Inheritance 

 of Acquired Characters. Organic Selection - - - 491 



HEREDITY 



Weismann's Views on Germ-Plasma. Influence of Environment on Germ-Cells, 

 Experiments of Yung on Tadpoles, and Schmankewitsch on Crustaceans. 

 Galton, Karl Pearson, and Mendel 492 



