424 



GENERAL PRINCIPLES 



of the male characters in the next generation depends upon 

 the colors, plumage or song, which are fitted to meet with the 

 approval of the female. Sexual selection also occurs in other 



Fig. 261, — Myrrh, a xerophytic plant of the Arabian desert. There are few 

 leaves and the spiny branches offer protection against grazing animals. (From 

 Sayre.) 



classes of animals. A particularly interesting case is found 

 among spiders. Here the males are often much smaller than 

 the female, and strive to gain her favor by series of movements 

 which may be called dancing. 



