408 C. J. Sundcvall on the Wings of Birds. 



at its base^ in the form of a tubercle^ which, in living or 

 recently shot birds, often seems to conceal the scapular 

 tubercle. Hence if we take the measurement from it we get 

 only the actual length of the os humeri, but not the length 

 from the scapular tubercle. The Coccyges show many con- 

 siderable differences in this respect, and partly approach the 

 Song-birds, and partly the Gallinre and E-aptores. In the other 

 orders named the same edge is often directed upwards or 

 pressed backwards, as in Coluinba. This, therefore, causes 

 the base of the humerus not to stand out so broadly and not 

 to conceal the true scapular tubercle in fresh birds; but 

 the latter is always perceptible from without, immediately 

 in front of the shoulder-joint. 



The length of the cubitus must also be particularly men- 

 tioned. The birds which feed their young and possess 

 available posterior toes [Aves altrices : " Nesthocker,^^ Oken ; 

 Oscines, Coccyges, Accipitres) have the cubitus longer than 

 the humerus, so that its anterior extremity (with the carpus) 

 stands even with, or somewhat in front of, tlie shoulder -and 

 the breast. In the other birds, however, which have a raised 

 ^oWqx k,c. {Aves prcECOces : ^'Nestfliicliter,^' Oken; Gallinae, 

 Grallfce, Anseres), it is in general shorter, even shorter than 

 the humerus itself. This condition, however, is modified in 

 this way : that in all birds which fly strongly, and especially 

 in all which have long hand-feathers, the cubitus is longer, 

 in order to furnish space for the thicker or more numerous 

 pennce cubitales, and through this the carpus projects further 

 in front of the breast. The contrary occurs in the bad fliers. 



We see, therefore, in the lowest Water-birds, the Pygo- 

 podes, as also in Mergus, that the cubitus is much shorter 

 than the humerus, and nearly equally so in the FuligulcB; it 

 is somewhat shorter than the humerus in Anas and in Cygnus 

 gibbus, equal to it in Cygnus musicus and Anser cinereus ; and 

 somewhat projecting in the smaller species of the genus 

 Anser, although the carpus still stands behind the shoulder- 

 tubercle. The same in Carbo, Procellaria, Diomedea. But 

 in Sterna and Larus the carpus always stands somewhat in 

 front of the shoulder-tubercle. 



