THE SKULL IN BIKDS. 245 



The vomers vary more than almost any other bones of the 

 skull. They underlie and embrace the inferior edge of the 

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

 birda 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 Coracomorphoe, and seem to be 

 always separate in the Woodpeckers. The coalesced vomers 

 constitute a very large and broad bone in most HaiitCB, and in 

 the TinamomorphoB ; a narrow elongated bone pointed in 

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

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

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

 be obsolete. 



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

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

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

 majority of birds the maxilla sends inward a maxillo-palatine 

 process (Fig. 83, mxjx), which, sometimes, is mere thin lamel- 

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

 Ratitm and the Desmognathce (Fi^. 84), the maxillo-palatine 

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



Jl/U 



Tlfl. S4. — The tinder surface of tlie cranium of the S^firetan' bird (^Gypogernvii^). ns an ex- 

 ample of tlicDosmoiniathousaiTrangement. J/JT^., maxillo-palatine process ; Bpt, bbsl 

 ptciygjid piocOBSca. 



