FALCONIDAE. 

 I. THE MAMMILLAE LAYER. ') 



A. Coloured green: Accipitrinac (genera Circus, Asiur and Accipiter), 

 Buteo and Pernis. 



B. Coloured white: Falco and Cerchncis. 



1. Spotted: Accipiter, Buteo, Pernis, Falco and Cerchncis. 



2. Spotted variably: Circus cyaneus. 



3. Unspotted as a rule: Circus pygargus, acruginosus and Astur. 



II. THE COHERENT -') LIME LAYER. 



A. Quite white: Accipitrinac and Buteo. 



B. Superficially coloured: Pernis, Falco and Cerchncis. 



1. Spotted: Accipiter, Buteo, Pernis, Falco and Cerchncis. 



2. Spotted variably: cyaneus. 



3. Unspotted as a rule : Circus pygargus, acruginosus and Astur. 



In contrast with the oocyanin which occurs as a calcium-compound 

 in layer I, the oorhodein is only congluiinated very superficially 

 with layer II. 



As regards eggs of the Accipitrinac and of Buteo, the brightness 

 of the green colour internally, when light shines through the shell, 

 as well as the more or less prominent occurrence externally of a 

 sea-green colour, depend on the greater or smaller thickness of this 

 layer; in other words: the eggs which look whitest on the outside, 

 show through darkest green internally. 



') This layer is joined on the inside very closely fo the outside of the un- 

 coloured layer (impregnated with calcium-salts) of the shell-membrane. 



") This layer is not interrupted by openings connected with each other, as 

 is the case with the mammillae layer. 



