CONTENTS. 



BOOK I.— MALE AND FEMALE. 

 CHAPTER I. 



PACE 



The Sexes and Sexual Selection - 3_j^ 



I. Primary and secondary sexual characters. 



II. Illustrations from Darwin. 



III. Darwin's explanation by sexual selection. 



IV. Criticisms of sexual selection — 



(a) Wallace. 

 (0) Brooks. 



(c) St George Mivart. 



(d) Others. 



CHAPTER II. 



The Sexes, and Criticism of Sexual Selection - - 14-26 



I. Search for a broader basis. 



II. Differences in general habit, &c. Males active, females 

 passive. 



III. Differences in size. Males smaller, females larger. 

 Pigmies and exceptions. 



IV. Secondary differences in color, skin, &c. Males 

 katabolic, females anabolic. 



V. Sexual selection : Its limits as an explanation. 



Postulate of extreme aesthetic sensi- 

 tiveness. 



Darwin and Wallace combined and 

 supplemented. 



Sexual selection a minor accelerant, 

 natural selection a retarding action, 

 on constitutional differentiation. 



CHAPTER III. 



The Determination of Sex (Hypotheses and Obser- 

 vations) --------- 27-35 



I. The period at which sex is settled. Ploss, Sutton, 

 Laulanie\ &c. 



