Ueithrum 

 /Clavicle 



A. Dogfish 



Scapula- 

 Coracoid- 



B. Reptile (primitive) 



Scapula 



Clavicle 



Glenoid' 

 fossa 



Coracdd 



Inter- 

 Clavicle 



Uernum 

 D. Monotreme 



Acromion process 

 Glenoid fossa^ 



Scapula 



Clavicle 

 Sternum 



E. Man 



Fig. 97. Comparative Anatomy of the Shoulder Girdle. The Dogfish has 

 a single pair of cartilages meeting ventrall3^ The primitive reptile (B) 

 and the Monotreme (D) have a complete girdle. The Placental Mammal 

 (E) shows the reduction of the corycoid bone to a process of the scapula, 

 and the development of the scapular spine. Diagrams (A), (B), (C) and 

 (D) are ventral views; (E) is an anterior view. 



