407 
C. J. Sundevall on the Wings of Birds. 
Parus and Passeres). They seem to be longest in Corvus, in 
which they reach a little over the half of the body, and 
shortest in Hirundo and Certhia (and probably in many of 
the short-winged tropical forms), in which they only reach 
one third. It must be remarked that precisely those which 
have the shortest wing-bones are the best and the worst fliers 
of the whole order. 
Two special osteological conditions cause some alterations 
in the above-cited measurements, although these are rarely 
of much importance. It must be remarked, however, in the 
first place, that these, as well as all forms in the skeletal 
structure of birds, are subject to many exceptions, and by no 
means indicate the affinities of the species with the same 
certainty as the external feathery covering. This is there¬ 
fore noticed rather to give a distinct idea of the constitution 
and measurements of these parts than to furnish definite 
characters. 
The first relates to the constitution of the shoulder itself. 
In the Song-birds the os coracoideum is, in general, slender, 
and projects as a short, somewhat inwardly-directed process 
in front of the articular surface of the humerus. The 
humerus is attached at the very front of the trunk, and pro¬ 
jects nearly as far forward as the true scapular tubercle (of 
the os coracoideum) . This bone (humerus) is therefore here 
but little shorter than the measurement just given, or nearly 
half the length of the body. In the Water-birds, Waders, 
Raptorial birds, Gallinse, and in the greater number of the 
Coccyges, on the contrary, the os coracoideum is generally 
thicker, and projects as a very large shoulder-tubercle, like 
a somewhat longer piece of the same bone, right in front of 
the articular surface of the humerus. The humerus, there¬ 
fore, is attached somewhat further behind the shoulder- 
tubercle, and consequently loses something more of the stated 
length. Besides this, the great upper edge of the humerus 
for the attachment of the muscles of the shoulder (repre¬ 
senting the tuherc. majus humeri ) projects, in the Song-birds, 
directly outwards horizontally from the articular surface, by 
which means the humerus stands out strongly transversely 
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