318 Evolution and Adaptation 
differ conspicuously from the common peacock in the color 
of their secondary wing-feathers, scapulars, wing-coverts, and 
thighs, and are, I think, more beautiful; they are rather 
smaller than the common sort, and are always beaten by 
them in their battles, as I hear from the Hon. A. S. G. Can- 
ning. The females are much paler-colored than those of 
the common kind. ‘Both sexes, as Mr. Canning informs me, 
are white when they leave the egg, and they differ from the 
young of the white variety only in having a peculiar pinkish 
tinge on their wings. These japanned birds, though appear- 
ing suddenly in flocks of the common kind, propagate their 
kind quite truly.” 
In two cases, in which these birds had appeared quite sud- 
denly in flocks of the ordinary kind, it is recorded that 
“though a smaller and weaker bird, it increased to the ex- 
tinction of the previously existing breed.” Here we have 
certainly a remarkable case of a new species suddenly 
appearing and replacing the ordinary form, although the 
birds are smaller, and ave beaten in their battles. 
Darwin has given an admirably clear statement of his 
opinion as to the causes of variability in the opening para- 
graph of his chapter dealing with this topic in his “ Animals 
and Plants.” Some authors, he says, “look at variability as a 
necessary contingent on reproduction, and as much an original 
law as growth or inheritance. Others have of late encouraged, 
perhaps unintentionally, this view by speaking of inheritance 
and variability as equal and antagonistic principles. Pallas 
maintained, and he has had some followers, that variability 
depends exclusively on the crossing of primordially distinct 
forms. Other authors attribute variability to an excess of 
food, and with animals, to an excess relatively to the amount 
of exercise taken, or again, to the effects of a more genial 
climate. That these causes are all effective is highly probable. 
But we must, I think, take a broader view, and conclude that 
organic beings, when subjected during several generations to 
