pointed out, differed in no essential from that of the typical 

 avian wing. In some points, however, it has changed con- 

 spicuously. For the bones have become greatly flattened, 

 and the several parts of the wing — arm, forearm, and hand — 

 can no longer be bent upon one another in the Z-shaped 

 fashion of normal wings, while the " quill " or " flight- 

 feathers " have been reduced to so small a size that they are 

 unrecognizable. 



132 



