1867.] PROF. HUXLEY ON THE CLASSIFICATION OF BIRDS. 4^7 



or less ossified. The baslpterygoid processes are represented by oval 

 facets, sessile upon the rostrum, and placed so far forward that the 

 surfaces which articulate with them are situated close to the anterior 

 extremities of the pterygoid bones. In this respect, in the rudi- 

 mentary condition of the inner lamina of the palatine bone, and in 

 the circumstance that the. angle of the mandible is strongly produced 

 and upcurved, these resemble the Gallinaceous birds. They differ 

 from the latter not merely by their " desmognathism " but by the 

 absence of the rounding off of the postero-external angle of the pa- 

 latine, which is so marked in the Fowls, and by the great proportional 

 length of the region of the skull, which corresponds with the attach- 

 ment of the lachrymal bone (Fr to Na, nearly, in fig. 18). 



In Ibis, Platalea, and Phcenicopterus the maxillo-palatines not 

 only unite across the vomero-palatine fissures, but, becoming enlarged 

 and spongy, fill the base of the beak. The basipterygoids, rudi- 

 mentary in Phcenicopterus, are absent in Platalea and Ibis. The 

 angle of the mandible of Phcenicopterus has the same prolongation 



Fig. 19. 



Under view of the skull of Ardea cinerect. The letters as before. 



