SEXUAL SELECTION 823 



males to 100 females. As these numbers are tolerably large, 

 and as tbey are drawn from all parts of England, during 

 several years, we may with muob confidence conclude that 

 with the domestic horse, or at least with the race-horse, the 

 two sexes are produced in almost equal numbers. The 

 fluctuations in the proportions during successive years are 

 closely like those which occur with mankind, when a small 

 and thinly populated area is considered; thus in 1856 the 

 male horses were as 107.1, and in 1867 as only 92.6, to 100 

 females. In the tabulated returns the proportions vary 

 in cycles, for the males exceeded the females during six 

 successive years ; and the females exceeded the males during 

 two periods each of four years: this, however, may be ac- 

 cidental ; at least I can detect nothing of the kind with man 

 in the decennial table in the Eegistrar's Report for 1866. 



Dogs. — During a period of twelve years, from 1857 to 

 1868, the births of a large number of greyhounds, through- 

 out England, were sent to the "Field" newspaper; and I am 

 again indebted to Mr. Tegetmeier for carefully tabulating 

 the results. The recorded births were 6,878, consisting of 

 3,605 males and 3,273 females, that is, in the proportion 

 of 110.1 males to 100 females. The greatest fluctuations 

 occurred in 1864, when the proportion was as 95.3 males, 

 and in 1867, as 116.3 males to 100 females. The above 

 average proportion of 110.1 to 100 is probably nearly correct 

 in the case of the greyhound, but whether it would hold 

 with other domesticated breeds is in some degree doubtful. 

 Mr. Cupples has inquired from several great breeders of 

 dogs, and finds that all, without exception, believe that 

 females are produced in excess; but he suggests that this 

 belief may have arisen from females being less valued, and 

 from the consequent disappointment producing a stronger 

 impression on the mind. 



Sheep. — The sexes of sheep are not ascertained by agri- 

 culturists until several months after birth, at- the period 

 when the males are castrated; so that the following returns 

 do not give the proportions at birth. Moreover, I find that 



