419 
C. J. Sundevall on the Wings of Birds. 
wards, towards the remiges. The inner branch, which in all 
other feathers is an accessory plume, seems therefore in 
these to have been fully developed, while the outer branch 
quite disappears, for it is entirely deficient, and has not even 
persisted in the form of an accessory plume. These feathers 
constitute two series (one of which, however, often disap¬ 
pears), which may be regarded as corresponding to the first 
and second series of covert-feathers (or possibly the quill- 
feathers and greater covert-feathers of the upper surface !). 
They often retain a rigidity and straightness and an external 
form which give them some resemblance to quill-feathers. 
On the cubitus the feathers of the first of these two series 
are firmly attached, and just like the remiges, with the inner 
(posterior) margin free, covering the outer (anterior) margin 
of the next feather; but in the second series they are movable 
and, more than any other wing-feathers, can be suppressed; 
further, they lie with the margins in the opposite direction 
to the former, so that the outer edge of each feather is free 
and covers the inner edge of the next one. This is so con¬ 
stant that I have never found an exception to it; and when 
either of the two series is entirely deficient, we can recognize 
by the position of the margins which it is that remains. The 
two series are continued upon the hand, but here they are 
often interrupted or divergent. In those birds in which the 
cubital remiges are continued beyond the joint upon the 
humerus (Gallinse, Raptorial birds, Waders, Water-birds), 
the second series of reversed feathers is continued in the 
same way, but not the first (see fig. 4, o, nos. 7 & 2 ). 
In all Song-birds the whole of the first series is so com¬ 
pletely deficient that not a trace of it remains. The second 
series consists usually of small feathers with downy edges, 
which are concealed by the following ones; but in Corvus , 
Garrulus , Troglodytes , and Cinclus they are larger and firmer; 
in Ampelis garrulus and in some Passeres (e. g. Pyrrhula ) 
they are concealed everywhere except upon the middle part of 
the hand, where they project beyond the following feathers. 
In all the other orders, on the contrary, the first row ap¬ 
pears always to occur; and if either of them is wanting or 
