170 



GENERAL ORNITHOLOGY. 



the gist of dromcBognathism; it is exhibited in several ways, (a) In Struthio alone, fig. 75, 

 the very sliort vomer, home upon the rostrum, articulates neither with palatines nor with ptery- 

 goids, but with the maxUIo-palatiues ; and the palatines, which are remote from the rostrum, 

 advance beyond the maxiUo-palatines, as in most birds. (6) In Rhea, the vomer is as long as 

 usual in birds, and articulates behind with the palatines and pterygoids,'but does not join the 

 maxillo-palatines in front ; the short palatines unite with the inner and posterior edges of the 

 thin fenestrated maxillo-palatines. (c) In Casuarius and Dromtsus (cassowary and emeu), 

 the long vomer articulates behind with the palatines and pterygoids, and unites in front with 

 the maxillo-palatines ; these are flat, imperforate, and solidly joined to the premaxillse ; the 

 palatines are short, (d) The extinct Dmornis had flat imperforate maxUlo-palatine plates 

 uniting solidly with the premaxOlse, and probably with the vomer, as in Dromceus. (e) In. 

 Apteryx, the long vomer unites with palatines and pterygoids behind ; short broad palatines 



>"s«^^ 



Fig. 76. — DromaognatTuMB 

 skull of tinamou {7%namu8 

 robustus) ; copied by Shufeldt 

 from Hujdey. Letters as be- 

 fore; Mxp, tnaxillo-palatine. 



suture obliquely with flat imper- 

 forate maxillo- palatine plates, 

 which unite both with premax- 

 Ulary and vomer. (/) The tin- 

 amous, DronuBognathcB (fig. 76) 

 " have a completely struthious 

 palate " ; vomer very broad, 

 uniting in front vrith broad max- 

 Ulo-palatine plates as in Dro- 

 mtsus; behind articulating with 

 posterior ends of palatines and 

 anterior ends of pterygoids, both 

 of which are thus prevented, as 

 in all RatitcB, from any extensive 

 connection with the rosti'um ; 

 baaipterygoid processes springing 

 from body of sphenoid, not from 

 its rostrum, articulating with 

 pterygoids very near the pos- 

 terior or outer ends of the latter ; 

 head of quadrate with a single 

 articular facet, as in Ratites. 



PlTlX' 



— Pa, 



Pig. 77. — Sehizognatlums skull of 

 common fowl, nat. size, from nature, 

 byDr.R.W.Sliufeldt, U.S.A. Letters 

 as before ; Pa, palatine. A -^ ' 



VW.W^"- 



Scbizognathism (Gr. crxtfa), schiso, I cleave) is the kind of 

 "cleft palate" shown by the columbine and gallinaceous birds, by the waders at large, and 

 many of the swimmers (see fig. 77). In this general case, the vomer, whether large or small, 

 tapers to a point in front, wiile behind it embraces the basisphenoidal rostrum, between the 

 palatines ; these bones and the pterygoids are directly articulated with one another and with 

 the basisphenoidal rostrum, not being borne upon the divergent posterior ends of the vomer ; 

 the maxillo-palatines, usually elongated and lamellar, pass inwards over \wnder, when the 

 skull is viewed upside-down, as it usually is] the anterior part of the palatines, with which 

 they unite and then bend backwards, along the inner edge of the palatines, leaving a broader 

 or najTower fissure between themselves and the vomer, on each side, and do not unite with one 

 another or with the vomer. It foUows from this that in the dry skuU of a plover, for instance, 

 which shows the schizognathous arrangement extremely well, " the blade of a thin knife can 

 be passed, without meeting with any bony obstacle, from the posterior nares alongside the 

 vomer to the end of the beak." There are several groups of birds which exhibit the schizo- 

 gnathous plan, with ulterior modifications of palatal and other characters, (a) The colum- 



