SKELETON. 605 



extends the rod-like columella. The lower jaw originally 

 consists of four membrane bones dentary, splenial, 

 angular, and surangular ; and one cartilage bone the 

 articular. The hyoid consists of a flat "body," with 

 anterior and posterior " horns." 



The pectoral girdle consists of sabre-like scapulae ex- 

 tending dorsally over the ribs, of stout coracoids sloping 

 ventrally and articulating with the sternum, of the clavicles 

 which are united by the interclavicle to form the merry- 

 thought. 



The sternum bears a conspicuous keel, is produced 

 laterally and posteriorly into two xiphoid processes, and 

 bears articular surfaces for the coracoids anteriorly, for the 

 ribs laterally. 



The skeleton of the wing includes the stout humerus, the 



Isch. 



\Ac. Ml. 



FIG. 211. Side view of pelvis of Cassowary. 

 //., ilium ; Isck., ischium ; Pb.> pubis ; Ac., acetabulum. 



separate radius and ulna (the latter the larger), two free 

 carpals, a carpo-metacarpus of three metacarpals fused to 

 one another and to some carpal elements, and three digits 

 the thumb with one joint, the first finger with two joints, 

 the second with one. 



The pelvic girdle consists of dorsal ilia fused to the 

 complex sacral region, of ischia sloping backwards, and 

 of pubes or post-pubic processes running parallel to the 

 ischia. The incomplete ossification of the socket or 

 acetabulum, and the absence of ventral symphyses, are 

 also noteworthy. 



The hind limb consists of a short stout femur, a tibia to 

 which the proximal tarsals are fused (forming a tibio-tarsus), 



