35 



iv. Neo-Lamarckians, vs. Neo-Daiivmiatts. 

 The inheritance of acquired characters. 

 The all-sufficiency of natural selection. 



3. The Factors of Organic Evolution. 

 i. Variation and Heredity. 



(Darwin, Origin of Species, Chap. V. ; Brooks, Heredity, pp. 

 140-165; Wallace, Darwinism, pp. 41-125 ; Lloyd Morgan, 

 Animal Life and Intelligence, pp. 61-75; Bateson, Materials 

 for the study of Variation ; Cope, Primary Factors of Organic 

 Evolution, pp. 21-73.) 



Variation and the inheritance of variations, the basis 

 of any theory of evolution. 



a. Kinds of Variation. 



(i) As to distribution. 



Variation in the individual. 



Acquired. 

 Congenital. 



Variation in the species, Racial Variation. 



Race. Variety. Sub-species. 

 No sharp line to be drawn between charac- 

 ters of the family, variety, and species. 



(2) As to quality. 



Substantive. 



Chemical composition. Color. Size. Pro- 

 ■^ portions. 



Meristic. 



Pattern. Symmetry. Homoeosis. 



Other qualities. 



Age at which various characters are acquired. 



Acclimatization. 



Habits. 



Change of function. 



