V! 



FORM AND FUNCTION 131 



Plumage. Iris. 



Red-backed Buzzard. ..To a great extent light brown ..Light brown. 



Cinereous Vulture .. ..Dusky Dark brown. 



Foster's Mil vagtj Mainly black Very dark. 



Shag 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 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. As a rule 

 the Iris is brown in young birds. The brighter tints 

 come with adult years, and in some species they are 

 limited to the male. 1 



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 Diet, 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 



