696 C. J. Sundevall on the Wings of Bird^. 



In Aptenodytes (which, at least as regards the plumage 

 is decidedly the lowest of all forms of birds) all the wing- 

 feathers are very small and hard, and have an external 

 resemblance to scales, which are cleft at the margin into a 

 fringe. Like the body-feathers in the same genus, they 

 cover the surface uniformly, without interspaces, like the 

 scales of fishes and reptiles, and form on both sides from 

 25 to 30 rows, without any difference except that those to- 

 wards the quill-margin of the wing are somewhat larger, 

 so that they more distinctly cover the roots of the next row. 



In all other birds the number of series is much less (at the 

 utmost 12 on each side) ; they leave considerable inter- 

 spaces, and are of quite different nature. 



As regards the different series, we may accept the follow- 

 ing kinds of wing-feathers : — 



(1) Wing-quills (Pennse alares, Remiges, Linn. & 111.) are 

 only a single row, which are seated in the posterior margin 

 of the wing and are tlie largest of all. All the others are 

 visually named coverts (tectrices). 



(2) Large coverts (Tectrices majores; Pteromata, 111.), 

 a series of feathers which lie immediately over the roots 

 of the quill-feathers, inserted in the skin behind the muscular 

 layer. 



(3) Second series of coverts, which are also seated in 

 the fold of skin behind the true arm or hand. They often 

 show the peculiarity that they lie in a reverse position to the 

 preceding, as to which more hereafter. 



(4) Small coverts (Plumse or Tectrices minores, bra- 

 chiales, cubitales, digitales, so-named according to the part 

 upon which they are seated) . They form from three to five 

 series, and are placed upon those parts of the skin which 

 enclose the bones and muscles of the limb. They are wanting 

 upon the cubitus in all birds which possess singing-muscles 

 at the lower larynx, but occur in all other birds. 



(5) Arm-fold feathers, or the anterior small feathers of the 

 wing (Plumse antecubitales, or Tectrices minimse), are seated 

 in several rows upon the fold of skin in front of the arm 

 itself. 



