AVES. 



451 



Order I. — RatitcE. 



These are nearly all large birds which all show a degen- 

 eration of the wings, in some cases to mere vestiges, in cor- 

 relation to which the carina of the sternum is lost, giving it 



Fig. 31 



-Ventral Surface of the Skull of an Ostrich x 4. 



{Ad nat.) 



X Premaxilla. 



Premaxilla. 



Lacrymal. 



Jugal. ™ 



Quadrato- 

 jugal. 



Palatine Process 



of Maxilla. 

 Vomer. 



!i i «» , Rostrum. 



Palatine. 

 ^ Pterygoid. 



/ Quadrate 



Basisphenoid. 



Squamosal. 



^1?-^ 



\^y ^^ X5^^/ 



Occipital Foramen 



Condyle. Magnum. 



Note the absence of teeth, single occipital condyle and quadrate-suspensorium. 



a rounded appearance. The hind-limbs are always large and 

 powerful. These birds exhibit certain structural features 

 which may be regarded as of a primitive nature. The 

 feathers have no hooked barbules, and, as a rule, they are 

 evenly scattered over the surface of the body. The bones 

 of the skull are mostly still separated by sutures, and the 



