GAME-BIRDS. 



THE SAND-GROUSE. ORDER PTEROCLETES. 



The sixteen species comprising this small Order, intermediate 

 in its affinities between the Pigeons {Columhce) and the True 

 Game-Birds {Gallhice), are all included in one family, Ptero- 

 clidcE. Their general structure presents many striking Colum- 

 bine characters, as in the vocal organs, pterygoid bones, and the 



Fig. I. — Skull of jP. exuslus. 



Fig. 2. — Skull of /'. cxiistus. 



presence of basipterygoid processes {l>p) in the skull (Fig. i), 

 the shoulder-girdle, sternum, and especially the great deltoid 

 process of the humerus, or upper-wing bone ; but the digestive 

 organs are like those of the True Game-Birds. Among other 

 distinctive characters maybe mentioned the " schizorhinal" 

 Q ' ^ 



