x CONTENTS 



CHAPTER PAGE 



XVII. THE ORIGIN AND DEVELOPMENT OF ORGANISMS: 



HEREDITY AND VARIATION .... 325 



The Origin of the Living Machine Not Ex- 

 plained. The Forces Which Have Produced 

 Organisms. Conformity to Type. Divergence 

 from Type. 



XVIII. THE ORIGIN OF THE LIVING MACHINE: ADAP- 



TATION; THE FORCES OF ORGANIC EVOLU- 

 TION 342 



Adaptation. The Theory of Evolution. 



XIX. CLASSIFICATION AND DISTRIBUTION . . . 364 



Classification (Taxonomy) . The Significance 

 of Classification. An Outline of the Classi- 

 fication of the Living World. Distribution 

 of Animals in Space and Time. Distribution 

 of Organisms in Time: Paleontology. 



GLOSSARY-INDEX 387 



