411 
C. J. Sundevall on the Wings of Buds. 
with the insertion of the tail [Columba, Coracias, Capri- 
mulgus, most Psittaci, Ficus viridis, lynx), rarely a little 
shorter ( Alcedo , Platycercus, and some other Australian 
Psittaci), but often J longer ( Cuculus , Pici varii et nigri); 
they are much shorter (J) only in Trochilus and Cypselus, 
which, in all respects, have these feathers so peculiarly 
formed. 
In the Oscines, as usual, we meet with less variation. 
In a single form, Cinclus , only have I found the anterior 
arm-feathers not reaching to the root of the tail; they 
attain only f of the trunk. In Hirundo and Sturnus they 
extend just to the end of the body, in Turdus and Fringilla 
usually a little (about or less) beyond it, in most about 
and in some (e. g. Corvi, Garruli, Pari) still further (about J) 
beyond the end of the body. It would seem as if, in Para- 
disea apoda, they reach nearly ^ beyond the body (i. e. to 
nearly twice the length of the body), but I have only seen 
stuffed specimens of this genus. 
It appears from what has been stated above that the 
length of these feathers, and consequently the breadth of 
the wing, varies in a great degree according to the generic 
form to which they belong, but they also vary a little between 
nearly allied species. A very slight difference in their length, 
such as can only be expressed by a small number which 
might be believed to be of no consequence ( e . g. of the 
length, 3-5 millim. in a bird the size of a Sparrow), never¬ 
theless produces a considerable increase or diminution in the 
whole surface of the parachute formed by all the cubital 
feathers together, which is not only easily recognized by the 
eye, but may also have an influence upon the power of 
flight. But leaving out of consideration the variation in the 
species, it would seem that these feathers are in general 
longest in the Song-birds, that they gradually diminish 
throughout the other Orders, and are smallest in the Water- 
birds. It ought also to be remarked that the length of the 
cubital feathers is much less subject to variation in young 
birds than the hand-feathers, which grow forth later. 
We have seen that many weak-flying birds have long arm- 
