1906. J OP THE TRACHEOPHONE PASSERES. 141 



Philepittidte (text-fig. 50 b), from a moderately broad base and 

 slope obliquely backwards till they reach the vomer, when they 

 curve so that their free ends run parallel with the long axis of the 

 skull. In the Pteroptochinfe these processes appear to spring from 

 the inner extremity of the quadi'ato-jugal bar, that is to say they 

 are given off by the extreme postero-internal angle of the maxilla, 

 instead of springing from the middle of this bone as in the 

 Philepittidfe. They curve backw^ards and inwards till they reach 

 the vomer, when they turn sharply backwards and run parallel 

 therewith, terminating only when they touch the downward keel 

 of the palatine. 



In the Synallaxinas and Acanthosittidfe these processes are of 

 great length and slenderness, curved towards the middle line, 

 slightly wider at their free ends, and extending backwards so as 

 to meet the median descending keel of the palatines. In Pseudo- 

 colcqjtes (text-fig. 50 c) the palatine processes of the maxilla may 

 be taken to represent a halfway stage between those of the 

 Dendrocolaptinge on the one hand, and the specialised form which 

 they present in the Synallaxinse as a rule. Arising from a broad 

 base they take the form of a pair of tongue-shaped laminae, under- 

 lying the middle of the vomer and presenting a convex border 

 forwards, and a deeply concave border directed towards the 

 palatines, with the median and downward keel of wdiich they 

 come in contact. 



The quadrato-jugal bar aflibrds no matter for comment. 



The Vomer, Pterygoid, and Pcdatine. 



The vomer (text-fig. 50 a-f) appears to have preserved its 

 simplest form in the Formicariidse. Here, as in ThcmmopMlus 

 and Batara (text-fig. 50 e), it is wide and truncated anteriorly, 

 has a long and broad body, and terminates in two moderatel}'" 

 long limbs, which will probably be found, in the nestling skull, to 

 extend backwards to meet the pterygoid. 



In the Pittidfe the vomer is of considerable size. Deeply 

 notched anteriorly, it extends backwards for a considerable 

 distance, a moderately long body giving place eventually to a pair 

 of long limbs. Though relatively narrower, the vomer of the 

 Pipridse is of the same shape. In the Conopophagidfe it is 

 relatively shorter and produced anteriorly into a pair of long'^ 

 " horns," due to the fusion and ossification of the concha vestibuli 

 (text-fig. 50 a). In the Pteioptochinas these adjuncts to the 

 vomer are of great size and terminate in semiossified cartilage. 

 But the body of the vomer is here greatly sliox'tened, so much so 

 that the breadth is greater than the length, and from this abbre- 

 viated base two long limbs run back to fuse with the dorsal 

 lamina of the palatines : though it is evident, from the great 

 length of the hemipterygoid element, that in young skulls this 

 vomer and the pterygoid will be found in actual contact. In the 

 Philepittidse (text-fig. 50 b), the vomer, though of considerable 

 length, is extremely reduced laterally, a small feeble body being 



