C. J. Sundevall on the Wings of Birds. \\7 



very small undeveloped feather-rudiments, covered up by the 

 next following perfect feathers. In older birds in the summer 

 plumage scarcely a trace of them is usually visible. 



This remarkable structure is so peculiar to those birds 

 which have the inferior larynx furnished with five pairs of 

 muscles, that I have been unable to find any other form 

 except Cypselus which resembles them in this respect ; but 

 it occurs in the whole of thera without a known exception, 

 and consequently forms a certain external character for 

 them*. In every Song-bird, even when sitting with folded 

 wings, and in stuffed specimens, we recognize this deficiency 

 at the first glance ; it causes the wing to exhibit only a small 

 number of coverts, and these to occupy an inconsiderable 

 space in comparison with those in the wings of species 

 belonging to other orders (see figs. 10, 11). 



All other birds have these feathers developed. In Picus 

 and XJpupa, which of all those which have no song-muscles 

 most resemble the type of the Song-birds and seem to con- 

 stitute the real transition to thera, the second and third series 

 are fully develcfped, but the first is incomplete, so that it 

 merely consists of a few feathers towards the carpus, and all 

 are so short that they project but little over the next follow- 

 ing ones, and therefore may easily be overlooked in dried 

 specimens. Except these I know no form in which they are 

 less distinct or perfect. Three series occur in the Psittaci, 

 all Raptorial birds, most of the smaller Waders, and in Anas ; 

 four in Coracias, Cuculus, Gallinula, Limosa, Lestris, and 

 Fuligula ; five in Columba, Tetrao, Numenius, Podiceps, Co- 

 lymhus, and Larus, as also in Carbo, which has them dark- 

 bordered. A more special study of them will no doubt repay 



* I have recently had the opportunity of examining a softened skin of 

 Menura lyra, and convinced myself that this bird also agrees perfectly 

 with the Song-birds in this respect ; it ceases therefore to be a probable 

 exception, just like the other two, Picm and Vpupa, which I previously 

 regarded as such. On the other hand, I afterwards found that Cypselus 

 has these feathers exactly as in the Song-birds, which was previously 

 accidentally overlooked, probably on account of the size of the covert- 

 feathers which occur. 



