VI FORM AND FUNCTION 131 
Plumage. Iris. 
Red-backed Buzzard ..To a great extent light brown... Light brown, 
Cinereous Vulture .. .. Dark brown. 
Foster’s Milvago ... .. Very dark. 
Shag cecainsiaasecemnesn Dark with green gloss......... ..Emerald green. 
Indian Kite ... .......A good many whitish feathers.. Nearly white. 
Indian Owl ... ........Much of it black ............ .....Dark brown. 
Flamingo ........ ..... Light pink................... ...Light yellow. 
Javan Fish Owl .. .. ..Some light brown on nearly all 
its feathers .......0...0.... Bright light yellow. 
But the eye is not always light or dark according to 
the shade of the plumage. The Crowned Pigeon, 
whose plumage is a light blue-gray, has eyes of a rich 
scarlet, just the colour of holly-berries. For the first 
few months of his life, the Gannet’s eyes are almost 
black, but they soon turn to a pale, almost white, hue, 
long before he has exchanged the dusky-gray attire of 
his youth for the snow-white of his maturity. Asarule 
the Iris is brown in young birds. The brighter tints 
come with adult years, and in some species they are 
limited to the male. 
The Ear. 
I shall first briefly describe the main features of the 
human ear, then point out the chief differences between 
it and the same organ in birds. The essential part 
is in the sidewall of the skull ; and here there is a bony 
“labyrinth” consisting of three winding tubes of bone, 
which are filled with fluid (L, in fig. 33). There is 
1 Dr. Gadow (Newton’s Dict. of Birds, vol. i., p. 230) refers to 
a paper on this subject by Th. A. Bruhin in Zool. Garten, 1870, 
pp. 290-295, which I have not read. 
K 2 
