ARTICULATION OF THE WING. 309 



stiffness. But we must not proceed much farther in 

 the consideration of this exquisite piece of mechanism : 

 — it would not only afford study for years, but 

 remain in great part an unexplained wonder after we 

 had exercised the longest life upon it. 



But, admirable as is the structure of this moving 

 part of the wing, it would fail in producing its office 

 if the point to which it is attached, and the organs by 

 which it is moved, did not partake of the same 

 character : for without this it would be like a well- 

 made tool or a powerful weapon placed in an unskilful 

 hand. 



The sternum is the grand bone upon which the 

 articulation of the wing at the shoulder-joint, and the 

 muscles which move that joint, are founded; and there- 

 fore, the general power of every wing may be judged 

 of more from that bone than from any other single part. 



But, in order to have a clear understanding of the 

 relative power of wings, it is necessary to examine 

 carefully all the bones which support the point to 

 which the wing is articulated, or which afford insertion 

 to the muscles by which it is moved. It has been 

 already mentioned, in the general notice of the struc- 

 ture of birds, that the three bones which support that 

 point are the coracoid, the scapula, and the branch of 

 the furcal. The articulation is more immediately 

 upon the coracoid, though the shallow socket in 

 which the head of the humerus plays, is often in 

 part formed by the scapula, with the arm of the fur- 

 cal bones against the other two on the inside, beyond 

 the socket, and as far as their extremities ; and imme- 

 diately behind the head of the coracoid, to the outside 

 of which the scapula is applied, there is a foramen 

 or hole, which serves as a pulley, through which the 

 tendons of the muscles that raise the wing pass. The 



