STEKNA OF THE STRUTHIONID^. 



317 



This sternum is oval, without any keel, and bears 

 sonae resemblance to the breast-plate of a tortoise ; 

 and the coracoids, whose principal use is to support 

 the bone, and preserve the form of the anterior part 

 of the chest against the weight of the bird, the pre- 

 sence of the atmosphere, and casualties, without 

 having any direct strain to bear when the bird is in 

 motion, are short, broad, and flat. 



The following figure is a side view of this sternal 

 apparatus. 



The outline of the sternum of this bird is, it will be 

 seen, very convex, with merely a trace of a keel at the 

 anterior part, near the junction of the coracoids. 

 The ribs are articulated far forward, and they are 



