444 THE DESCENT OF MAN. 



rather larger in the male. When the male is furnished with 

 leg-spurs the female almost always exhibits rudiments of them, 



the rudiment sometimes consisting of a mere scale, as in Gallus. 



Hence it might be argued that the females had aboriginally been 

 furnished with well-developed spurs, but that these had subse- 

 quently been lost through disuse or natural selection. But if this 

 view be admitted, it would have to be extended to innumerable 

 other cases; and it implies that the female progenitors of the ex- 

 isting spur-bearing species were once encumbered with an in- 

 jurious appendage. 



In some few genera and species, as In Galloperdix, Acomus, and 

 the Javan peacock (Pave muticus), the females, as well as the 

 males, possess well-developed leg-spurs. Are we to infer from 

 this fact, that they construct a different sort of nest from that 

 made by their nearest allies, and not liable to be injured by their 

 spurs; so that the spurs have not been removed. Or are we to 

 suppose that the females of these several species especially re- 

 quire spurs for their defense? It is a more probable conclusion 

 that both the presence and absence of spurs in the females result 

 from different laws of inheritance having prevailed, independent- 

 ly of natural selection. With the many females in which spurs 

 appear as rudiments, we may conclude that some few of the 

 successive variations, through which they were developed in the 

 males, occurred very early in life, and were consequently trans- 

 ferred to the females. In the other and much rarer cases, in 

 which the females possess fully developed spurs, we may conclude 

 that all the successive variations were transferred to them; and 

 that they gradually acquired and inherited the habit of not dis- 

 turbing their nests. 



The vocal organs and the feathers variously-modified for pro- 

 ducing sound, as well as the proper instincts for using them, 

 often differ in the two sexes, but are sometimes the same in both. 

 Can such differences be accounted for by the males having ac- 

 quired these organs and instincts, whilst the females have been 

 saved from inheriting them, on account of the danger to which 

 they would have been exposed by attracting the attention of birds 

 or beasts of prey? This does not seem to me probable, when we 

 think of the multitude of birds which with impunity gladden the 

 country with their voices during the spring.' It is a safer con- 

 clusion that, as vocal and instrumental organs are of special ser- 

 vice only to the males during their courtship, these organs were 



' Daines Barrington, however, thought it probable ('Phil. Transact." 

 1773, p. 164) that few female birds sing, because the talent would have 

 been dangerous to them during incubation. He adds, that a similar 

 view may possibly account for the inferiority of the female to the male 

 in plumage. 



