SEC. IV ANATOMY OF BIRDS 255 



Coracomorphw, nearly synonymous with Passeres, relates to the 

 palatal structure exhibited by a raven (Fig. 79), as typical of that of 

 Passeres at large. The vomer is a broad bone, truncate in front and 

 deeply cleft behind, embracing the sphenoidal rostrum in its forks. 

 The palatines have produced postero-external angles. The maxillo- 

 palatines are slender at their origin, extending inward and back- 

 ward over the palatines and under the vomer, where they end free, 

 being united neither with each other nor with the vomer. This 

 disconnection of the maxillopalatines is qwad hoc " schizognathous," 

 of course ; but such condition, in association with the peculiarities of 

 the vomer, is segithognathous. The nasal septum in front of the 

 vomer is often ossified in aegithognathism, and the interval between 

 it and the premaxillse filled up with spongy bone; but no union 

 takes place between this ossification and the vomer (Huxley). 

 According to Parker, the distinguishing character of the segitho- 

 gnathous type is the union of the vomer with the alinasal wall and 

 turbinals. He distinguishes four styles : (a) Incomplete ; very curi- 

 ously exhibited by the low Turnix, which stands near the gallina- 

 ceous birds. (6, c) Complete, as represented under two varieties, 

 one typified by the crow, an Oscine Passerine, the other by the 

 Clamatorial Passerines Pachyrhamphus and Pipra. (d) Compound, 

 i.e. mixed with a kind of desmognathism, as noted above. " Vomer 

 truncated in front " is the general expression for the condition of 

 that bone in the segithognathous type ; it is frequently massive in 

 that direction, and of endlessly varied configuration. 



Saurognathism (Gr. o-avpos, sauros, a lizard; Fig. 80). Accord- 

 ing to Huxley the woodpeckers exhibit a " degradation and simpli- 

 fication of the segithognathous structure." The peculiarities of the 

 palate of these birds (including Picidce, Picumnidce, and lyngidos) are 

 so decided that Parker proposes to call them saurognathous. The 

 structure is very difficult to make out, and may be understood best 

 by study of the accompanying figure, copied from Parker. The 

 maxillopalatines, mxp, are very slight, not extending inward beyond 

 the outer margin of the palatines, and being sometimes quite rudi- 

 mentary. In front of them, an additional little palatal plate of the 

 maxillary, pmx, is developed. The vomers, v, are delicate paired 

 rods on each side of the median line. The postero-external angle of 

 the palatine is either rounded off or obtuse-angled. Where the 

 broad main part of the palatine suddenly narrows is developed an 

 interpalatine process, ipa. The ethmopalatine plates, epa, or internal 

 superior plates of the palatine, which are of variable length, are con- 

 nected by the most marked mediopalatine ossification, mpa, seen in 

 the class of birds. Bridges of bone are deposited along the inner 

 borders of the palatines ; such are the septomaxillaries, smx, and 

 other formations which, like the mediopalatine, serve to bind the 



