SKELETONS OF BIRD AND REPTILE 



13 



The Breastbone and the Bones that meet at the shoulder- 

 joint. 



A powerful wing would be of no use without 

 powerful machinery for moving it, and a lizard with 

 a bird's wings would be no more able to fly than any 



Fig. 5. — (a) Sternum of Iguana, with interolavicle, coracoid, precoracoid, and 

 clavicle. 

 cl, clavicle ; co, coracoid ; icl, interclavicle ; pco, precoracoid ; st, sternum ; 

 (b) Coracoid, scapula, and clavicle of fowl, 

 co, coracoid ; sc, scapula ; cl, clavicle. 



ordinary lizard. In the bird's skeleton the enormous 

 breastbone suggests a great deal. They must be 

 strong muscles which have so strong and big a bone 

 to which to attach themselves. No two things can 

 be more unlike than the breastbones of the bird and 

 the lizard, and the same may be said of the associated 

 bones. In the lizard the whole apparatus is flat and 



