44 



A HISTORY OF BIRDS 



process of the premaxilla and the maxillo-palatine processes, 

 in this last matter resembling the Tinamous. Finally, they 



III. 14. — Stages in the Evolution of the Avian Palate 



A, Dromasus. B, Gallus. C, Rhea. D, Tinamou. E, Larus. F, Portion 

 of the palate of a Penguin to show the hemipterygoid. G, The hemipterygoid, 

 side-view. Vo. = Vomer. Mx. = Maxillo-palatine. Pt. = Pterygoid (I, 111. 

 A. Pc, 111. C = Pterygoid). Pa. = Palatine. H. pt. = Hemipterygoid. 



will be found to articulate with the pterygoids by means of a 

 ti'ue joint — opposed bones having glenoid surfaces. 



Now between the type of palate, as we have remarked, 



