86 



ORGANS OF SUPPORT, 



FIG. 45. 



extensively moveable, as organs of prehension ; hence the 

 peculiar forms presented by these regions of the skeleton in 

 birds, as seen in the skeleton of the griffon vulture, vultur 

 fulvus, (Fig. 45.) As the body is supported wholly on the 

 legs, the toes extend to a great length, to afford a broad 

 base, the legs are placed 

 forwards upon the sides of 

 the pelvis, the trunk is in- 

 clined backwards upon these 

 organs of support ; the neck 

 and head are proportionally 

 elongated, to reach the food 

 upon the ground, and the arms 

 and hands are folded longitu- 

 dinally along the sides of the 

 trunk, as in the bats. The trunk 

 of birds is almost as fixed 

 as that of a tortoise, to give 

 strength to the muscles em- 

 ployed in flight, and the ver- 

 tebrae of the neck and tail 

 are almost alone moveable. 

 The rapid ossification and 



anchylosis here affects not only the bones of the skull, but 

 the whole bones of the pelvis, the lower jaw, the scapular 

 arch, the clavicles, and the sternum. This tendency to 

 ossification affects the sterno-costal cartilages, the tendons 

 of the muscles of the legs, the sclerotic coat of the eye, the 

 rings of the trachea, and the inferior larynx. 



The vertebrae of the neck are always more numerous than 

 in the mammalia, and are sometimes more than three times 

 the number common to that class. They have their articu- 

 lar surfaces so directed that the neck is naturally concave in 

 front at the upper part, and convex in front at the lower 

 part, presenting more or less of that sigmoid curviture, 

 which is so conspicuous in the long-necked 'birds. The 

 oblique processes, as seen in those of the swan, (Fig. 46. 

 h 9 hj) are generally long, narrow, and diverging, admitting 

 with safety of very extensive motion. The spinous pro- 

 cesses (i, i,) are very short, to offer no obstruction to the 

 movements of the neck. The transverse processes (/,/,) 



