Tiii CONTENTS. 



PAGE 



lizards, 123. Substitutionary theories of the origin of 

 secondary sexual characters, 124. 



APPENDIX: References to books and papers discussing 

 sexual selection, 125. Wolff's' critical exposition of weak- 

 nesses in sexual selection, 126. 



CHAPTER VI, 



JDARWINISM DEFENDED 129 



Position of the defenders of Darwinism, 129. Reaction 

 against the too speculative positions of Haeckel and 

 Weismann, 130. "Haeckelismus," 130. Weismannism, 

 131. Struggle between Neo-Darwinians and Neo-La- 

 marckians, 133. Concessions of the Neo-Darwinians, 134. 

 Answer to objection concerning the too slight character of 

 fluctuating or Darwinian variations to serve as handles for 

 natural selection, 138. Answer to the objection concern- 

 ing the linear and quantitative character of Darwinian 

 variation, 139. Answer to the objection that selection can- 

 not produce many-branched descent, 142. Answer to the 

 statement that selection can produce continuous change 

 or evolution, but not species, 143. Answer to the objec- 

 tion concerning the production by selection of co-adaptive 

 and highly complex specialisations, 144. Answer to the 

 objection concerning the over-development of specialisa- 

 tions, 146. Discussion of the difficulty that natural selec- 

 tion has with structural degeneration, 146. The Darwinian 

 answer to the expressions of doubt about the rigour of 

 selection, 148. Answer to the objections to the sexual 

 selection theory, 148. Discussion of the objection to the 

 derivation of evidence for natural selection from the facts 

 of artificial selection, 150. Tayler's general defence, 153. 

 APPENDIX: Weldon's experiments on Carcmus, 158. 

 Tayler's explanation of degeneration by natural selection, 

 162. Plate's explanation of character fixity in domestic 

 animals, 163. 



CHAPTER VII. 



DARWINISM DEFENDED (Continued}: PLATE'S CON- 



CILIATORY DEFENCE 164 



Plate, a fair-minded Darwinian champion, 164. Answers 

 to the objection based on the slight character and inutility 

 of Darwinian variations, 165. Many slight differences at 



