1808.] 



PROF. HUXLEY ON THE ALECTOROMORPH^. 



.309 



Fig. 12. 



fC6% 



Fig. V2. The right tar.so-metatarsus of O^jisthocomus, viewed from in fi-ont. tlio 

 side, aud behind, with the proximal and distal ends. 



The basal phalanx of the hallux is slender, curved, and consider- 

 ably longer than that of the middle digit, as in the Pigeons. In 

 Corythuix the two are equal in length. 



In the skull, the strong rostrum, united with the frontal region by 

 a well-marked transverse hinge (figs. 13, 14, p. 310), and the for- 

 ward extension of the nasal bones, narrowing the nasal apertures, 

 gives the cranium a superficial resemblance to that of the Musopha- 

 (jidcR. Closer examination, however, shows that the two are ex- 

 tremely different. In Corijthaix the hinge lies, as usual, in front of 

 the lachrymal bones, which are connected by sutural union alto- 

 gether with the frontals, and the rostrum is formed by the prse- 

 maxillcC and nasals. But in Opisthocomus the hinge lies behind the 

 lachrymals, which have completely coalesced with the nasals and 

 form an integral part of the rostrum. 



In Tetrao urogallus and in Crax, the inner margins of the lachry- 

 mals are connected almost wholly with the nasals, and their pos.e- 

 rior margins are truncated and unite with the frontals only by a 

 short, more or less transyerse, suture. If the sutures between the 

 nasals and preemaxillee, on the one hand, and the frontals, on the 

 other, were as open as this is, the rostrum would have a hinge just 

 like that of Opisthocomus ; and ankylosis of the lachrymals with the 

 nasals would complete the resemblance. 



The mandible of Corythaix bears a good deal of general resem- 

 blance to that of a Pigeon. In Opisthocomus, the mandible is like 

 that of Diduncidus in general form, and has the peculiar flanging 

 out of the upper margins of the rami, which is absent in Curythaix, 

 but is so characteristic of the mandible in most Pigeons. 



The i)alatine bones (fig. l(i, p. .Sll) have much resemblance tn 



