405 
C. J. Sundevall on the Wings of Birds. 
The number of cubital feathers depends upon the length of 
the cubitus upon which they are inserted; and the length of 
the cubitus, again, is in proportion to the length of the 
humerus; we must therefore take these parts into considera¬ 
tion. From what has been said, it is clear that all birds 
which have many cubital feathers also have long wing-bones 
and, consequently, long wings. We have just spoken of the 
wings which are long in consequence of the length of the 
hand-feathers; these have generally shorter wing-bones. 
The length of the wing-bones can only be determined by 
comparison with the trunk; and this must be calculated 
from the shoulder to the last caudal vertebra (the base or 
insertion of the tail), to which the rectrices are attached. 
The shoulder is distinguished by the usually projecting end 
(or process) of the os coracoideum which receives the clavicle 
(furcula ), and which may be distinctly recognized under the 
skin, immediately in front of the humerus. The articulation 
of the humerus is situated immediately behind this tubercle, 
in the anterior part of the trunk itself. The first principle 
of determination is, therefore, to measure how far the pos¬ 
terior wing-fold (the elbow, or the posterior ends of the 
humerus and cubitus) extends upon the trunk when the 
wing is folded up. Of all birds, Diomedea exulans , which has 
the greatest number of cubital feathers, has also the longest 
wing-bones; these reach considerably (by or 32 millim.) 
beyond the posterior extremity of the trunk. They are 
shortest in Trochilus and Cypselus , in which they do not 
reach quite one fourth of the trunk. In general they are 
longest in Water-birds, Waders, and Raptorial birds. Thus 
they reach in Diomedea (all species) more or less beyond 
the base of the tail; in Pelecanus and Fregata nearly to the 
extremity of the body (J ?) ; in Carbo rather more than J (in 
Dysporus much further). 
Among the Gavise they reach in Larus to about in 
Sterna to ±§; in the Procellarise they vary from | (in Tha - 
lassidroma) to §. 
In Cygnus and Anser they reach §; but in the Ducks 
[Anas, Fuligula, Mergus) only a little more than |. 
SER. V.-VOL. IV. 2 G 
