152 
The amount of white on the scapulars too, varies greatly. 
Some have only a single feather, others nearly the whole sca- 
pulars white, and I have some specimens, perfect adults, as 
regards the plumage on every other point, but exhibiting no 
trace whatsoever of white on the scapulars. 
Although individuals of each stage differ, as above indicated, 
very greatly inter se, still the examples of each stage, taken as 
a body, are sharply separated from those of every other stage; 
and connecting links, between the four stages, are greatly 
needed. At present, we have four types; Ist, the striped ; 
2nd, the uniform pale brown, with double wing bands; 3rd, 
the uniform dark brown, without wing bands; 4th, the black- 
ish brown with orange buff head, and nape; but no really 
intermediate forms, such as are absolutely necessary, to enable 
us to compile a correct history of the various changes of plumage. 
In Europe, the changes of plumage seem even less known 
than here. In the [bis for October, 18638, the Rev. Mr. Smith, 
in his note on the birds of Portugal remarks : 
“T entertain considerable doubts whether the only specimen 
of this bird in the Museum of Lisbon is a genuine Imperial 
Eagle, inasmuch as there is not a single trace of white on the 
scapulary, feathers; and though Professor du Bocage, whose 
attention I called to the fact, accounted for it, by declaring the 
bird in question to be immature, I cannot find that this dis- 
tinctive characteristic of the species is ever wholly absent, 
though doubtless it is more conspicuous in adult birds.” 
To this latter sentence, the editor appends the remarks, 
“Tt has usually been supposed that the contrary was the case !” 
Now my review of the bird’s various stages of plumage, shows 
pretty clearly; Ist, that at any rate until its fourth year, this 
species never shows any white on the scapulars, and 2nd, that 
it is the fully adult, and these only, that exhibit this specific 
character. To assist comparison, I subjoin further on, detailed 
measurements and descriptions, taken frem fresh birds, in 
different stages of plumage. I shall be anxious to learn, whether 
Huropean Museums contain specimens of the European Impe- 
rial Eagle, in all the four above described stages. Here and 
there a bird in each stage, seems to present some connecting 
link, with some other stage; but these links, except between 
the 38rd and 4th stages, are very weak, and my only good 
reason for believing that all four belong to one and the same 
species, is, that after ¢xamining nearly a hundred freshly killed 
specimens in one stage or another, I have been unable to detect 
any structural difference ; the dimensions vary, in the same sex, 
very widely ; but the differences are as great between examples 
