162 
SEXUAL SELECTION: BIRDS. 
Part II. 
siderable length, even at greater length than its intrinsic 
importance deserves ; for various curious collateral points 
may thus be conveniently considered. 
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 Gallinacege 
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 Ifemale progenitors of the existing spur- 
bearing species were once encumbered with an in- 
j urious appendage. 
In some few genera and species, as in Galloperdix, 
Acomus, and the Javan peacock (Pavo muticus), the 
^ Bechstein, ‘ Naturgesch. Deutsclilands,’ 1793, B. iii. s. 339. 
