C. J. Sundevall on the Wings of Birds. 395 



Along the hinder margin of the cubitus and hand the skin 

 likewise forms a large, but firm and hard fold {f,g), in which 

 the large wing-feathers are seated. Indeed it is by the con- 

 siderable development of the feathers that the skin is drawn 

 out into a fold which surrounds the roots of the feathers. 



The differences in the length of the different joints of the 

 wing will be referred to further on, under the head of the 

 Remiges cubitales. 



2. The wing consists of the feathers which clothe the an- 

 terior extremity, in the skin of which they are seated arranged 

 in rows (series) which are parallel to the bones and to the 

 posterior margin of each individual joint. 



The feathers are generally directed backwards, so that 

 each series covers that lying immediately behind it (or at 

 least its root) . In general there are about the same number 

 of feathers in each series, for they are arranged in quin- 

 cunx, so that each feather is situated in the middle of an 

 interval in the two nearest series. Their points of insertion 

 may therefore form rows in three different ways (see figs. 2, 6) ; 

 but the feathers themselves form series only in one way, 

 because all those which are placed in the same series are 

 nearly of the same size and nature, while those in different 

 series most frequently differ considerably from each other 

 (see figs. 3, 4, 7, 8). The smallest and softest are placed in 

 front ; towards the posterior margin of the wing the feathers 

 increase in size and firmness, so that the quill-feathers which 

 occupy the posterior margin itself are the largest of all. In 

 the enumeration of the series we must therefore necessarily 

 begin with the quill-feathers and call them the first series ; the 

 second, third, &c. follow in order forwards. The foremost 

 series are so small and indistinct that one can hardly distin- 

 guish them unless we proceed in order from the posterior ones. 



In each series we must call those feathers outer (externse) 

 which are placed nearest to the apex of the wing ; and inner 

 (internse) those which are situated nearer to the base of the 

 wing and the body. As the outermost feathers arc always 

 the easiest to find, we must commence the ordinal numbers 

 (1, 2, 3, &c.) from them. 



