Family FALCONIDAE. 

 (Plates 100—109). 



Proper to all the genera is the short-oval or rounded-oval shape, 

 with more or less pronounced transitions towards the spherical 

 egg-shape; the latter occurs especially in the genera Pcrnis and Circus. 



The texture of the shell, which is judged of according to the 

 layer referred to below under II, is in the case of the genera Falco 

 and Cerc/ineis sharply distinguished by its much finer, more uniform 

 granulation from that of the other genera; the genus Accipitcr ap- 

 proaches closest to them in this respect. Pernis ') forms as it were 

 a transition towards Butco. Astur exhibits in general a coarse lime- 

 granulation, which in the case of Circus is slighty finer and closer, 

 in other words: is more united. 



In connection with the colour of the shell and the markings, I 

 now give a review respecting all the genera. 



') Rey separates (on wrong grounds, in my opinion) the genera Pandion 

 and Pcrnis from one another, as layer I is coloured green by oocyanin in both 

 genera; but in Pandion, firstly, the superficial colour of layer II is absent or 

 only occurs in a slight measure, and further, the markings are never so close 

 as in the case of Pcrnis; consequently, in the first mentioned genus the oocyanin 

 of layer I remains better visible when light penetrates through the eggshell. 



