THE ANATOMY OF BIRDS.— OSTEOLOGY. 169 



Certain other inward maxillary processes, which may or may not unite with the vomer, and so 

 bridge over the palate, are called se/^to-maxillaries (fig. 80, smx) ; and in some woodpeckers 

 yet other palate-processes appear (fig. 80, imix). 



The Pterygoid Bones (Gr. irrtpv^, ptenix, wing ; eidos, eidos, form ; figs. 62 ; 63, o; 



65, 66, 68, 69, 71, 80, pg; 75 to 79, Ft). Eetuming now to the quadrate, and going along the 

 inner arcade, we first encounter the pterygoid, — a generally rod-like, but variously twisted, 

 crooked, or expanded bone which makes the connection between the quadrate behind and the 

 palate bone before. The pterygoid is always freely jointed at both ends ; its posterior quadrate 

 articulation has been noted above ; its anterior connection is usually by little nipper-like claws 

 by which it " catches on" to the hind end of the palatine. In the ostrich (fig. 75, Ft) the 

 pterygoid expands into a scroll-like plate ; but its rod-like shape is usually preserved. Besides 

 passing very obliquely inward as it goes forward from the wide-apart quadrates to the narrow 

 rostrum in the axis of the skull, the pterygoid often bellies or elbows inwards in its course to 

 join the basisphenoidal beak, and be movably articulated therewith. In the majority of birds, 

 there is no such rostral articulation, or the pterygoid only touches the rostrum at its fore end 

 where it joins the palatal. In many, however, special articular facets, called hasipterygoid 

 processes (fig. 70, ap), are developed on the rostrum for the pterygoids to abut against and 

 glide over. In Carinate birds, excepting the tinainous (Dromcsognathce) , these processes are 

 forward on the beak, and the pterygoids articulate at or near their own fore ends, as well shown 

 in the fowl or duck, figs. 77, 78, Ft. In Eatite birds and tiuamous, the basipterygoids are 

 very long, flaring transverse processes, far back on the rostrum, at the sphenoidal base, and 

 the pterygoids articulate therewith at or near their own posterior ends (figs. 75, Btp, and 76). 



The Palatal or Palatine Bones (Lat. palatum, roof of the mouth ; figs. 62 ; 63, p; 65, 



66, 68, 69, 71, 11, 78, 80, pa; 75, 76, 79, PI) are a pair, approximately parallel and near the 

 mid-line, forming that part of the *' hard palate " or roof of the mouth which is not constructed 

 by the palatal processes of the maxillaries, or vomer. They are nearly always long thin bones, 

 among the most conspicuous parts when the dried skuU is viewed from below. Sometimes, as in 

 the ostrich (fig. 75, pi), they are remote from the axis of the skull and only connected in front 

 with the maxillaries and maxillo-palatines. In many birds they skip the maxillary parts in 

 going forward to be fused with the premaxillaries ; in most, probably, they form anterior con- 

 nections in one or another fashion with palatal parts both of maxillaries and of premaxillaries. 

 Behind, they always correctly articulate with the pterygoid. The mid-line connections made 

 in most Carinate birds (not in DromaBognathse) are variously ^vith the vomer, with the ros- 

 triun, with each other, or some or all of these relations at once. A long deeply-deft vomer 

 may by its posterior forks attach itself to the whole palatal mid-line, excluding tiie palatals^ 

 from the rostrum ; less extensive attachment of the same kind may permit the palatals to touch 

 each other and the rostrum posteriorly, while cutting them off" anteriorly ; also, a non-cleft 

 vomer may attach itself to the posterior extremity f)f the palatals, and bear them off the ros- 

 trum. The whole hard palate may fuse into an indistinguishable mass ; and in almost any 

 case the relations of the palatals to each other and their connections afi'ord some of the most 

 valuable zoological characters of great groups of birds. (Details figured and described beyond.) 

 Though very variable in configuration, as well as in connections, certain parts of a palatal may 

 usually be recognized, and conveniently named for descriptive purposes. Anteriorly, in the 

 great majority of birds, of whatever technical kind of palatal structure, the palatals are simply 

 prolonged as flat strap-like or lath-like bars running past the maxillary to the premaxillary 

 region ; and such simple band-like character may be preserved behind. Ordinarily, however, 

 the palatals expand posteriorly, becoming more or less laminar ; and in this i)late-like part 

 three surfaces may usually be recognized. One, more or less horizontal, flaring outward, is the 



