POSTSCRIPT 



Voi. I., pp. 287-289. — I have fallen into a serious and 

 unfortunate error, in relation to the sexual differences of 

 animals, in attempting to explain what seemed to me a 

 singular coincidence in the late period of life at which 

 the necessary variations have arisen in many cases, and 

 the late period at which sexual selection acts. The ex- 

 planation given is wholly erroneous, as I have discovered 

 by working out an illustration in figures. Moreover, the 

 supposed coincidence of period is far from general, and 

 is not remarkable ; for, as I have elsewhere attempted 

 to show, variations arising early in life have often been 

 accumulated through sexual selection, being then com- 

 monly transmitted to both sexes. On the other hand, 

 variations arising late in life cannot fail to coincide ap- 

 proximately in period with that of the process of sexual 

 selection. 



