1906. J OF THE TRACHEOPHONE PASSERES. 141 



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

 slope obliqviely 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 Pteroptochina^ these processes appear to spring fi'om 

 the inner extremity of the quadrato-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 backwards and inwards till they reach 

 the vomer, when they turn sharply backwards and rvm parallel 

 therewith, terminating only when they touch the downward keel 

 of the palatine. 



In the >Synallaxinpe and Acanthosittida? 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- 

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

 be taken to represent a halfway stage between those of the 

 Dendrocolaptinae 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 laminse, 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 which they 

 come in contact. 



The quadi'ato-jugal bar affords no matter for comment. 



The Vomer ^ Pterygoid^ and Palatine. 



The vomer (text-fig. 50 a-f) appears to haA'e preserved its 

 simplest form in the Formicariidae. Here, as in Thamnophilus 

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

 has a long and broad body, and terminates in two moderately 

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

 extend backwards to meet the pterygoid. 



In the Pittidee the vomer is of considerable size. Deeply 

 notched anterioi-ly, 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 Pteroptochina? these adjuncts to the 

 vomer are of great size and terminate in semiossified cartilage. 

 But the body of the vomer is here greatly shortened, 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 

 Philepittidae (text-fig. 50 b), the vomei", though of considerable 

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



