162 SEXUAL SELECTION : BIRDS. Part II. 



Before we enter on the subject of colour, more 

 especially in reference to Mr. Wallace's conclusions, 

 it may be useful to discuss under a similar point of 

 view some other differences between the sexes. A 

 breed of fowls formerly existed in Germany ^ in which 

 the hens were furnished with spurs; they were good 

 layers, but they so greatly disturbed their nests with 

 their spurs that they could not be allowed to sit on their 

 own eggs. Hence at one time it appeared to me pro- 

 bable that with the females of the wild Gallinacese 

 the development of spurs had been checked through 

 natural selection, from the injury thus caused to their 

 nests. This seemed all the more probable as the wing- 

 spurs, which could not be injurious during nidification, 

 are often as well developed in the female as in the 

 male ; though in not a few cases they are 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 with the species of Gallus. Hence it might 

 be argued that the females had aboriginally been fur- 

 nished with well-developed spurs, but that these had 

 subsequently been lost either through disuse or natural 

 selection. But if this view be admitted, it would have 

 to be extended to innumerable other cases ; and it im- 

 plies that the female progenitors of the existing 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 (Pavo muiicus), the 

 females, as well as the males, possess well-developed 

 spurs. Are we to infer from this fact that they con- 



5 Bechstein, ' Natm-gescli. Deutschlands,' 1793, B. iii. s. 339. 



