THE SKULL IN BIRDS. 



245 



The vomers vary more than ahnost any other bones of the 

 skull. They underlie and embrace the inferior edge of the 

 ethmo-presphenoidal region of the basis cranii, and, in all 

 birds in which they are distinctly developed, except the Os- 

 trich, they are connected behind with the palatine bones. In 

 most birds, they early unite into a single bone ; but they 

 remain long distinct in some Coracomorplicje^ and seem to be 

 always separate in the Woodpeckers. The coalesced vomers 

 constitute a very large and broad bone in most Hatitm^ and in 

 the Tlnamomorphm ; a narrow elongated bone pointed in 

 front in Schizognathce ; a broad bone deeply cleft behind, and 

 abruptly truncated in front, in CoracomorpliGe. In most Des- 

 mognathm the vomer is small ; and, sometimes, it appears to 

 be obsolete. 



The maxillae of birds are usually slender, rod-like bones, 

 articulating by squamous suture, in front, with the premaxillge, 

 aod, behind, with the equally slender jugals. In the great 

 majority of birds the maxilla sends inward a maxillo-palatine 

 process (Fig. 82, mxp^^ which, sometimes, is mere thin lamel- 

 la of bone, sometimes, becomes swollen and spongy. In the 

 Hatitce and the Desmogiiathce (Fig. 84), the maxillo-palatine 

 processes unite with the vomer, or with one another, and form 



-Mx. 



JS/it. 



Fig. 84. — ^The under surface of tie cranmm of the Secretary bird {Gypogeramis), as an ex- 

 ample of the DesmognathoiisanTaDgement. Mxp.^ maxillo-palatme process ; Bpt.^ basi 

 pterygoid processes. 



