3o 



THE EVOLUTION OF SEX. 



Boulenger, Legoyt, and others, and by some breeders of stock and 

 birds, but is denied by other practical authorities, and directly contra- 

 dicted by the recent statistics of Stieda, from Alsace-Lorraine, and of 

 Berner, from Scandinavia. 



Summary of Statistics bearing on Relative Number of Males and Females. 



The above table (in its upper part taken mainly from Hensen, 

 after CEsterlen) shows vividly how much the results of Stieda and 

 Berner conflict with the law of Hofacker and Sadler. In regard to 

 Berner' s statistics, it ought to be further noted that the figures quoted 

 refer to cases where the father or mother is only from one to ten 

 years the older. If the father be more than ten years older, the male 

 majority is 103.54; if tne mother be more than ten years older, the 

 proportion is 104.10 again, against Hofacker' s and Sadler's conclusion. 

 Compared with the above human statistics, Schlechter's results in 

 regard to horses also militate against the alleged law. 



In regard to plants, various naturalists have drawn attention to the 

 influence of age upon sex. The following observations are quoted by 

 Heyer: In Leo?ita?'us domeslica, according to Rumpf, the female plant 



