THE ANATOMY OF BIRDS.— OSTEOLOGY. 163 
Certain other inward maxillary processes, which may or may not unite with the vomer, and so 
bridge over the palate, are called septo-maxillaries (fig. 80, sma) ; and in some woodpeckers 
yet other palate-processes appear (fig. 80, pm). 
The Pterygoid Bones (Gr. aréepvé, pterux, wing; eidos, eidos, form; figs. 62; 63, 0; 
65, 66, 68, 69, 71, 80, pg; 75 to 79, Pt). Returning 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, Pt) 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 basipterygoid 
processes (fig. 70, ap), are developed on the rostrum for the pterygoids to abut against and 
glide over. In Carinate birds, excepting the tinamous (Dromeognathe), 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, Pt. In Ratite birds and tinamous, 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, 77, 78, 80, pa; 75, 76, 79, Pl) 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 skull is viewed from below. Sometimes, as in 
the ostrich (fig. 75, pl), 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 Dromeognathe) are variously with the vomer, with the ros- 
trum, with each other, or some or all of these relations at once. A long deeply-cleft vomer 
may by its posterior forks attach itself to the whole palatal mid-line, excluding the 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 of the palatals, and bear them off the ros- 
trum. ‘The whole hard palate may fuse into an indistinguishable mass; and in almost any 
ease the relations of the palatals to each other and their connections afford some of the most 
valuable zoélogical 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 plate-like part 
three surfaces may usually be recognized. One, more or less horizontal, flaring outward, is the 
