THE IBIS. 
FIFTH SERIES. 
.No. XVI. OCTOBER 1886. 
XXXIX .—On the Wings of Birds. By C. J. Sundevall. 
(Plates X., XI.) 
[Translated from tlie original Swedish of the 1 Kongl. Vetensk.-Akad, 
Handlingar/ 1843, by W. S. Dallas, 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 
2 F 
SER. V.-VOL. IV. 
