OSTEOLOGY OF BIRDS 



249 



OSTEOLOGY AND CLASSIFICATION OF THE ANSERES 



Formerly there were not a few systematic ornithologists who 

 entertained the opinion that the present group should contain not 

 only all the anserine fowls proper (Anatidae etc.), hut also the 

 flamingoes and perhaps the screamers (Palamedeidae) as well; 

 as has already been shown, however, the present writer dissents 

 from this view, to the extent of placing the flamingoes in a sub- 

 order by themselves, and proposes to restrict to the suborder here 

 to be osteologically considered, the swans, geese, ducks and mer- 

 gansers. From this it will be seen that the screamers, as well as 

 the flamingoes, are kept without the typical anserine assemblage, 

 an arrangement that I take to be quite in keeping with a natural 

 taxonomy. For, in so far as the osteology of the Palamedeidae 

 seems to indicate, they are separated from the Anatidae by a gap 

 fully as wide as the one that separates the Phoenicopteridae from 

 them. And, if we admitted the screamers into the present sub- 

 order, then there would be no valid reason for excluding the flam- 

 ingoes. Consequently to fulfil the ends of a natural classification, 

 the Palamedeidae are here considered to occupy a suborder apart, 

 to be designated as the Palamedeae. As a group they stand next 

 to the true Anseres. 



In the Check-List of North American Birds [A. O. U. 1895] 

 the "order" Anseres is made to contain the single family Anatidae. 

 This latter is divided into four subfamilies, viz : the Merginae ; the 

 Anatinae ; the Anserinae ; and the Cygninae. Of these the first 

 named contains the mergansers, two species of the genus Mer- 

 gus, and one of the genus Lophodytes. The subfamily Anatinae 

 contains the "River ducks," 1 with ten species and subspecies in the 

 genus Anas ; one each in Spatula. Dafila, Aix, and Xetta ; five in 

 the genus Marila, two in Clangula, one each in Charitonetta, 

 Histrionicus, Camptorhynchus (doubtless extinct), Eniconetta and 

 Arctonetta ; three and a subspecies in Somateria and four in 

 Oidemia ; and finally, one each in the genera Erismatura and 

 Xomonyx. Numerous species of geese are placed in the sul family 

 Anserinae, as three and a subspecies in the genus Chen ; two 

 and two subspecies in Anser ; four and four subspecies in Branta ; 

 one in Philacte, and two in Dendrocygna. YYe have three species 



1 In this edition of the A. O. U. Check-List all of the ducks in North America were 

 considered "River ducks," (even including the eiders! p. 114), but in the 2d edition 

 of that work the subfamily " Fuligulinae, Sea ducks " is introduced, the line being 

 drawn between A i x sponsa and Xetta r u f i n a . There exist no constant 

 osteological characters by which any such division as " River ducks " and " Sea ducks " 

 can be established, and, in reality, nothing of the kind occurs in nature, in so far 

 as these birds are concerned. 



