THE EVOLUTION OF SEX. 



truly part and parcel with the male or female constitution, they are 

 only of secondary importance in the reproductive process. The beard 

 of man and the mane of the lion, the antlers of stags and the tusks of 

 elephants, the gorgeous plumage of the peacock or of the bird-of- 

 paradise, are familiar examples of secondary sexual characters in males. 

 Nor are the females lacking in special characteristics, which serve as 



Fig. i. - Male and Female Bird-of- Paradise (Paradisea viinor). 

 From Catalogue of Zoological Museum, Dresden. 



indices of their true nature. Large size is one of the commonest of 

 these; while in some few cases the excellencies of color and other 

 adornments are possessed by the females rather than by their mates. 



The whole subject of secondary sexual characters has found its most 

 extensive treatment in Darwin's " Descent of Man" ; and to that work, 

 therefore, the more so as its limits exceed those of the present volume, 

 the reader must be assumed to make reference. All that can be here 



