Note on the Lacertilian Shoulder Girdle. 375 



expanded and quite primitive in type, while the coracoid is greatly 

 expanded and has two large openings. In Iguana, on the other 

 hand, both elements are greatly expanded and there are four large 

 fenestra?. 



In the embryo the scapula and coracoid are both originally 

 unfenestrated cartilaginous structures, which, however, become 

 fenestrated long before ossification begins. There thus seems good 

 reason to believe that the lacertilian girdle is merely a highly 

 specialised modification of the Sphenodon type and that it only 

 contains the two cartilaginous elements — scapula and coracoid. 



