OSTEOLOGY OF BIRDS I73 



the common migratory quail (Cot ur nix dactylisonans) 

 of Europe. 



Much excellent literature is in existence descriptive of the various 

 embryonic stages of the fowl from the egg to the adult ; and in this 

 connection the student should read the memoirs of Kitchen Parker 

 and of Professor Balfour, especially the Morphology of the Skull 

 and the Structure and Dci'clopinent of the Wing in the Common 

 Foii'l [Royal Soc. Lond. Phil. Trans. 1888] of the former author, 

 and The Elements of Embryology of the latter. There are also 

 many other works. 



OSTEOLOGY OF CALLUS BANKIVA 



Darwin, when he came to compare the extraordinary forms the 

 skull assumes in many of the domestic breeds of fowls with the 

 skull of the wild G . b a n k i v a , pointed out for us a number of 

 the salient features in the skull of the latter species/ and it will be 

 my aim here to discuss these more in detail, and without any at- 

 tempt to make comparisons with domestic species, touch more fully 

 upon the differences found in the skulls of the male and female 

 G . b a n k i V a , as seen in the two specimens now before me. In 

 doing this, I must once more remind my reader of a "fact that I 

 have so often insisted upon in other connections, and that is, that 

 the individual variation of the skull for the same species may be 

 marked to a marvelous degree in some specimens, and we may have 

 as an example a thick and unperforated interorbital septum in the 

 skull of one bird, and a thin one, showing a large vacuity in the 

 same osseous partition in the skull of another individual of the same 

 species. Still more manifest differences may extend to size and 

 even form of such parts as beak, brain case, and basitemporal area. 

 So, then, under such circumstances, the description I here present 

 for the skull of the Jungle fowl will hardly hold good for all de- 

 tails in other specimens of the same species, although, no doubt, 

 the main characteristics wdll be found descriptive of the vast ma- 

 jority of skulls. These remarks are equally applicable to the re- 

 maining parts of the skeleton. 



As is generally the case with gallinaceous fowls, the premaxillary 

 develops conspicuous nasal and maxillary processes ; the former 

 being longitudinally separated for their hinder two thirds, with the 

 posterior ends almost entirely covering the ethmoid where it makes 

 its appearance anteriorly between the frontals. In domestic fowls 



^Animals and Plants under Domestication, Darwin, C. Anier. ed., 1868. 1:315-21. 



