284 



STRUCTURE AND CLASSIFICATION OF BIRDS 



formula of the leg, as stated in the definition, is ABX Y + . 

 Both peroneals are present. The deep flexor tendons are 

 bound by a vinculum, which is single in Corythaix and 

 double in Schizorhis. 



The skull of Corythaix is barely desmognathous, and 

 by no manner of means especially like that of a cuckoo, 

 to which group the Musophagi have been often compared. 

 The hinge in the middle of the face is nearly complete, but 

 there is a bridge on each side, formed by an ankylosis 

 between the frontal and nasal. The holorhinal nostrils are 

 situated very far forwards, and each has, as Parker ' has 

 pointed out, an osseous fold upon the ossified internarial 

 septum. The maxillo-palatines diverge from each other 

 posteriorly for a much longer space than in any cuckoo. 

 The ascending laminae of the palatines come into contact 

 for a very brief space over the rostrum in front, and are 

 continued forward for a short distance as a sharp spike. 

 Between them lies a minute interpalatine splint (or vomer). 

 The interorbital septum is moderately fenestrate. The 

 lacrymal bones are of some size, and the descending process 

 is closely applied to, but does not fuse with, the square 

 ectethmoid process ; connected with both is a small os 

 uncinatum, which reaches the palatine.^ 



Bony fiostrils . 



Ectethmoid 



Palatines 



Maxillo-palatines 

 Jugal bar 



Close to fronto-nasal 



hinge. 

 Continuous with dorsal 



wall of orbit. 

 Ascending laminae come 



into contact posteriorly 



for a considerable 



space. 

 More completely fused.- 

 Expanded where it joins 



maxilla on, or close to, 



ventral surface. 



Musophagi 



Near end of bill. 



Not 30 continuous. 



Ascending laminae come 

 into contact anteriorly 

 for a short space. 



Less completely fused. 



Not expanded ; junction 

 with face higher up, 

 very much as in 

 parrots. 



In view of the general opinion as to the nearness of the 



• In his paper upon Opisthocomus. See below, p. 286, footnote '. 

 ^ J. T, BeinhabDt, rid. Medd. Kjobenhavn, 1871, p. 326. 



