GOLDEN PHEASANT 23 



show you the skin of the adult obscuva cock, but only some feathers plucked from his 

 breast and back, and the skins of his two brothers and of two of his sisters. An 

 examination of these breast-feathers plucked from obscura, and of some of the breast- 

 feathers of the cock marked ' semi-obscura^ will show the reason of, the so-called 

 ' duskiness ' of hue ; each feather has a bar of metallic green on the inner half, while the 

 outer end of it is red. You will observe in the Golden cock that the breast-feather is 

 red throughout. 



"Apparently, then, Thamnalea obscura is a hybrid recessive mutation, breeding 

 true, as shown in Elliot's plate and also in my experiment this year, according to 

 Mendel's law. I have used the word ' mutation,' but these birds may possibly be a 

 reversion to the ancestral parent form of both ' species ' of Thamnalea. 



" By whatever name it is called, this hybrid is undoubtedly a homozygote for 

 pattern and colour, pure and permanent, transmitting these characters to its descendants. 

 Cross-breeding between these two varieties of Thaumalea produces a new form, owing 

 possibly to the meeting of characters never previously combined, and as they are 

 constant it is evident these have an affinity and have become inseparable. 



"On such lines evolution might be conceived as having proceeded fairly rapidly 

 towards the separation of species." 



In this instance there seems to occur somewhat more variation in colour and pattern, 

 at least in the chicks, than we find in the black-throated birds from normal Golden 

 parents. But aside from this, the mutation is identical. So that whatever readjustment 

 of unit characters occurs in the production of this form, it may result from unstable 

 conditions in a normal pair of Goldens in captivity as well as in hybrids with an 

 Amherst cock and Golden hen for parents. It seems to me an excellent illustration of 

 the appearance of a true mutation species, induced in this case by captive and not feral 

 conditions, and quite comparable to the black-shouldered peacock. As the change in 

 colour is chiefly melanistic, it is doubtful whether we can consider the theory of atavism, 

 as the darkening of the scarlet is an advance in specialization, not a degeneration as in 

 the case of the xanthochroism in the masculization of the barren hens. 



Perhaps the most remarkable and surprising fact in connection with this mutation, 

 is the very distinct character both of colour and pattern in the natal down of the chicks. 

 These, as we have seen, actually differ much more from each other than do the fully 

 plumaged adult cocks — the reverse of what usually obtains among nearly related forms, 

 where the chicks are often indistinguishable, while greater and greater differences 

 become apparent as the ontogenetic sequence of plumages approaches the fully adult 

 stage. 



EARLY HISTORY 



The first important mention of this bird is by Albin in his "Natural History of 

 Birds," published in 1740, where he calls it the " Red Pheasant Cock from China," and 

 gives a very bizarre figure. Seven years later Edwards criticizes this, and in his turn 

 presents a plate of the " Painted Pheasant from China," as he terms it, with the entire 

 under-parts of a delicate pink. 



His summary of the knowledge of the bird at that date is as follows : " These birds 

 of late years are frequently brought from China : I have seen several of them in the 



