432 PROF. HUXLEY ON THE CLASSIFICATION OF BIRDS. [Apr. 11, 



Among the Gallinaceous Birds, the Phasianidce, Turnicidce, and 

 Pteroclidce all have basipterygoid processes, which are situated upon 

 the rostrum, and take the form of sessile, oval, articular facets for 

 the pterygoid bones. The palatine bones have long and slender an- 

 terior processes, and completely rounded-oflf postero-external angles. 

 They have generally small, and sometimes almost obsolete, maxillo- 

 palatines, and very imperfectly developed vomers, so that the vomero- 

 palatine clefts are wide and, usually, almost uninterrupted, through- 

 out their length, which is, relatively, very considerable. 



The angle of the mandible is prolonged and bent upwards, some- 

 times, as in Tetrao, acquiring a prodigious length. 



Fig. 14. 



Under view of the skull of Tefrno xiroqallus. From a specimen belonging to 

 W. K. Parker. Esq.. F.R.S. 



The letters as before. 



In the Megapodidce (e. g. TaleguUa) the maxillo-palatines take the 

 form of thin plates tapering to their free ends, which pass inwards 

 and then, before they reach one another, bend back at a right angle. 



