274 THE DESCENT OF MAN. 



sexual characters in animals of all classes, and shall 

 endeavor in each case to apply the principles explained in 

 the present chapter. The lowest classes will detain us for 

 a very short time, but the higher animals, especially birds, 

 must be treated at considerable length. It should be borne 

 iu mind that for reasons already assigned I intend to give 

 only a few illustrative instances of the innumerable 

 structures by the aid of which the male finds the female, 

 or, when found, holds her. On the other hand, all 

 structures and instincts by the aid of which the male con- 

 quers other males, and by which he allures or excites the 

 female, will be fully discussed, as these are in many ways 

 the most interesting. 



SUPPLEMENT ON THE PROPORTIONAL NUMBERS OF THE 

 TWO SEXES IN ANIMALS BELONGING TO VARIOUS 

 CLASSES. 



As no one, as far as I can discover, has paid attention to 

 the relative numbers of the two sexes throughout the 

 animal kingdom, I will here give such materials as I have 

 been able to collect, although they are extremely imperfect. 

 They consist in only a few instances of actual enumeration 

 and the numbers are not very large. As the proportions 

 are known with certainty only in mankind, I will first give 

 them as a standard of comparison. 



Man. In England during ten years (from 1857 to 1866) 

 the average number of children born alive yearly was 

 707,120, in the proportion of 104.5 males to 100 females. 

 Bui. in 1857 the male births throughout England wore as 

 105.2, and in 1865 as 104 to 100. Looking to separate 

 districts, in Buckinghamshire (where about 5,000 children 

 are annually born) the mean proportion of male to female 

 births during the whole period of the above ten years was 

 as 102.8 to 100, while in N. Wales (where the average 

 annual births are 12,873) it was as high as 106.2 to 100. 

 Taking a still smaller district, viz., Rutlandshire (where 

 the annual births average' only 730), in 1864 the male 

 births were as 114.6, and in 1862 us only 97 to 100; but 

 even in this small district the average of the 7,385 births 

 during the whole ten years was as 104.5 to 100; that 



