AVES. 451 
ORDER I.—Ravre. : 
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. 318.—VENTRAL SURFACE OF THE SKULL OF AN OSTRICH x $4. 
(Ad nal.) 
Premaxilla. 
Premaxilla, 
Rostrum. 
Nasal. 
Maxilla. 
Palatine Process 
of Maxilla. 
Vomer. 
Rostrum. 
Jugal. 
.Palatine. 
Pterygoid. 
¢ Quadrate 
Basisphenoid. 
sa Foramen 
‘ondyle. Magnum. 
Note the absence of teeth, single occipital condyle and quadrate-suspensorium. 
arounded 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 
