298 STRUCTUKE AND CLASSIFICATION OF BIRDS 



golds articulate by their anterior ends. The palatines too are 

 devoid of an internal lamina, and the angle of the mandible is 

 recurved and produced ; it is enormous, extended upwards, in 

 Tetrao. 



In the typical gallinaceous birds the maxillo-palatines 

 are generally small or even obsolescent. In Gallus hanhiva ' 

 they are triangular plates of fair size ; in Tetrao urogallus 

 (fig. 152) they are small, narrow, backwardly projecting 

 plates, not quite so long and thin, and not so curved as those 

 of Talegalla. In Ptilopachys they are somewhat inter- 

 mediate ; in CalUpepla californica they are still longer. In 

 Numida and Meleagris they are much the same. 



The lacrymals are not large,^ and have a feeble or aborted 

 descending process. It is very general for the post-frontal 

 and zygomatic processes to fuse and enclose a more or less 

 triangular foramen, and sometimes, as in Tetrao^ and Crosso- 

 ptilon, the zygomatic bar extends forwards a considerable 

 way in front of its junction with the other. 



The interorbital septum is sometimes {Coturnix, CalU- 

 pepla, Perdicula, Ptilopachys) considerably fenestrated. 



The vomer, in gallinaceous birds generally, is thin and 

 Splint-like. 



As to the Megapodes, there are some differences in the 

 skulls of the two genera Talegalla * and Megacephalon. The 

 latter has the well-known hammer-shaped projection of the 

 back part of the skull. In both genera the palatines are 

 slender, and there is some ossification of the nasal septum. 

 The interorbital septum is not much fenestrate, but it is 

 deficient in front. In Talegallathe maxillo-palatines are thin 



• Shufeldt, ' Observations upon the Morphology of Gallus bankiva,' &c. 

 Journ»Comp. Med. Surg. ix. p. 343. 



- Wood-Mason has described [Ann. Mag. Nat. Hist. xvi. 1875, p. -145) supra- 

 orbital bones in certain partridges. Cf. as to this point Tinamous, Fsophia, 

 and Mentira. . 



' Shufeldt, 'Osteology of the N. American Tetraonidce,' Bull. U. S. Geol. 

 Surv. vi. p. 309. 



^ The skeleton of this bird is described by Pakkee, ' On the Osteology of 

 Gallinaceous Birds and Tinamous,' Tr. Z. S. v. p. 160. See also W. K. 

 Pakkek, ' On the Structure and Development of the Skull of the Common 

 Fowl,' Phil. Trans. 1870, p. 159. 



