Chap. XVIII.] SUMMARY. 299 



ing horns of stags, and tlie elegant horns of certam ante- 

 lopes, though properly serving as weapons of offence or 

 of defence, have been partly modified for the sake of orna- 

 ment. 



When the male differs in color from the female, he gen- 

 erally exhibits darker and more strongly-contrasted tints. 

 We do not in this class meet with the splendid red, blue, 

 yellow, and green colors, so common with male birds and 

 many other animals. The naked parts, however, of cer- 

 tain Quadrumana must be excepted ; for such parts, often 

 oddly situated, are colored in some species in the most 

 brilliant manner. The colors of the male in other cases 

 may be due to simple variation, without the aid of selec- 

 tion. But when the colors are diversified and strongly- 

 pronounced, when they are not developed until near ma- 

 turity, and when they are lost after emasculation, we can 

 hardly avoid the conclusion that they have been acquired 

 through sexual selection for the sake of ornament, and 

 have been transmitted exclusively, or almost exclusively, 

 to the same sex. When both sexes are colored in the 

 same manner, and the colors are consj^iicuous or curiously 

 ari'anged, without being of the least apparent use as a pro- 

 tection, and especially when they are associated with va- 

 rious other ornamental appendages, we are led by anal- 

 ogy to the same conclusion, namely, that they have been 

 acquired through sexual selection, although transmitted 

 to both sexes. That conspicuous and diversified colors, 

 whether confined to the mafes or common to both sexes, 

 are as a general rule associated in the same groups and 

 subgroups with other secondary sexual characters, serv- 

 ing for war or for ornament, will be found to hold good 

 if we look back to the various cases given in this and the 

 last chapter. 



The law of the equal transmission of characters to 

 both sexes, as far as color and other ornaments are con- 



