THE SKELETON 25 



line continued forwards as a narrow opening 

 between the frontal bones and the interorbital 

 septum. 



The Skeleton of the Wing (Fig. 1) 



The thoracic limb of birds is modified for 

 purposes of flight and is commonly known as 

 the wing. The wing and its skeleton may be 

 divided into certain segments, as shown in the 

 following table : — 



r Scapula. 



(1) Shoulder-girdle . . -j Coracoid. 



I Clavicle. 



(2) Free part of the limb — 



{a) Arm . . Humerus. 



{b) Forearm . . Radius and Ulna. 



(c) Manus. 



a. Carpus. 

 13. Metacarpus. 

 7. Digits. 

 The narrow, thin, slightly curved, and sabre- 

 like scapula, or shoulder-blade, is placed nearly 

 parallel to the vertebral column, reaches almost 

 to the pelvis, and thus lies across most of the 

 ribs. At its cranial end is a concavity which 

 forms part of the articular depression for the 



