179 GENERAL ORNITHOLOGY. 
the gist of dromcognathism; it is exhibited iggg@veral ways. (a) In Struthio alone, fig. 75, 
the very short vomer, borne upon the rostrum, articulates neither with palatines nor with ptery- 
goids, but with the maxillo-palatines ; and the palatines, which are remote from the rostrum, 
advance beyond the maxillo-palatines, as in most birds. (b) 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 imner and posterior edges of the 
thin fenestrated maxillo-palatines. (¢) Ii Casuarius and Dromeus (cassowary and emeu), 
the long vomer articulates behind with the palatines and pterygoids, and unites im front with 
the maxillo-palatines ; these are flat, imperforate, and solidly joimed to the premaxille; the 
palatines are short. (d) The extinct Dinornis had flat imperforate maxillo-palatine plates 
uniting solidly with the premaxille, and probably with the vomer, as in Dromeus. (e) In 
Apteryx, the long vomer unites with palatines and pterygoids behind; short broad palatines 
suture obliquely with flat imper- 
forate maxillo- palatine plates, 
which unite both with premax- 
illary and vomer. (jf) The tin- 
amous, Dromeognathe (tig. 76) 
‘‘have a completely struthious 
palate”; vomer very broad, 
uniting in front with broad max- 
illo-palatine plates as in Dro- 
meus; behind articulating with 
posterior ends of palatines and 
anterior ends of pterygoids, both 
of which are thus prevented, as 
in all Ratite, from any extensive 
connection with the rostrum ; 
basipterygoid processes springing 
from body of sphenoid, not from 
its rostrum, articulating with 
pterygoids very near the pos- 
Fic. 77. — Sehizognathous skull of 
: common fowl, nat. size, from nature, 
head of quadrate with a single by Dr. R. W.Shufeldt, U.S.A. Letters 
skull of tinamou ( Tinamus articular facet, as in Ratite. as before; Pa, palatine. 
robustus); copied by Shufeldt 
from Huxley. Letters as be- 
fore; Mxp, maxillo-palatine. Schizognathism (Gr. cyifw, schizo, 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, while 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 narrower fissure between themselves and the vomer, on each side, and do not unite with one 
another or with the vomer. It follows from this that in the dry skull 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- 
gunathous plan, with ulterior modifications of palatal and other characters. (a) The colum- 
terior or outer ends of the latter ; 
