THE IBIS. 



FIFTH SERIES. 



No. XVI. OCTOBER 1886. 



XXXIX.— Ow the Wings of Birds. By C. J. Sundevall. 

 {Plates X., XI.) 



[Translated from the original Swedish of the * Kongl. Vetensk.-Akad. 

 Handlingar,' 1843, by W. S. DaUas, F.L.S.] 



Introduction. 

 As the differences in the feather-covering of the wings of 

 birds appear to be of the very greatest significance in the 

 systematic arrangement of that class, which otherwise seems 

 to present so few, or rather no certain, characters for the 

 larger divisions, a somewhat detailed description of them may 

 possess no little interest. People seem not to have supposed, 

 or to have been unwilling to believe, that such apparently 

 accessory parts as feathers could furnish reliable indications 

 of the internal organization of the different groups of birds, 

 which they sought in vain from other organs ; at least we 

 can scarcely explain in any other way why the very re- 

 markable differences in the structure of the wings were so 

 long neglected, although they are among the very first which 

 must strike the eye in the external examination of birds. 

 It is, however, a truth that every external part of an 

 animal can furnish equally certain indications of affinity or 

 distinction between species as an internal part of the body, 

 and that in this respect no order of precedence can be es- 

 tablished a priori. A character certainly does not possess 



SER. V. VOL. IV. 2 F 



