164 
GENEBAL OBNITHOLOGY. 
external lamina. It is well shown in a Passerine or Raptorial bird, where the postero-external 
angle (between the outer border and the posterior end) of the palatal is well-marked, or may 
be acutely produced ; there is no such lamina in a fowl, where the palatals are for the most 
part slender and rod-like. An internal, more or less vertically produced, plate to make the 
mid-line rostral or vomerine connection is the superior internal lamina, or medio -palatine pro- 
cess; very strong, for example, in a fowl, where it forms all the expanded part of the bone, and 
ends anteriorly as a sharp inter-palatine spur. The medio-palatine is probably to be regarded 
as the main body of the bone, being the most axial part, of the most extensive and varied con- 
nections. A third lip or plate of the palatal is the inferior internal lamina, looking downward ; 
it is generally very evident, but in a duck or fowl is reduced to a mere ridge, indicating where 
the superior internal and external laminae meet. A duck's palatals are quite different in ap- 
pearance from those of most birds, all the posterior parts just distinguished being reduced and 
constricted, while the fore ends, running abruptly into the hard-boned beak, are much expanded 
horizontally (fig. 78). The postero-external angles of the palatal (formed by the external 
lamina), even when much produced, may not reach as far back as opposite the pterygo-palatine 
articulation ; or they may surpass these limits, and when they do, such backward prolongation 
is called post-palatiue, the palate being considered to end at the pterygoids. In like manner, 
the maxillary processes of the palatals, or the palatal strips as prolonged into the premaxillary 
region, are called pre-palatines. The inner posterior process, by which the palatine is articu- 
lated with the pterygoid, is its pterygoid process. 
The Premaxillary Bones (figs. 62 ; 63, a; 69, 70, 71, 80, px; 75 to 79, pmx), also called 
Intermaxillaries, form most of the upper beak, attaining enormous development in birds, and 
reversing the usual relative size of premaxillary and maxillary. Mainly determining as they 
do the form of the upper mandible, their shapes are as various as the bills themselves of 
birds; but their generalized characters can be easily given. Each premaxillary, right and 
left, forms its half the bill ; the two are always completely fused together in front, commonly 
preserving traces at least of their original distinction behind. They are commonly called one 
bone, the premaxillary. Each is a triradiate or 3 -pronged bone ; one upper prong, the most 
distinct, called the nasal or frontal process, forms with its fellow the culmen (p. 104, fig. 26, h) 
of the bill. These processes, side by side, run clear up to ihe frontal bone in birds, driving the 
nasal bones apart from each other. Such a median fronto-premaxillary suture, with lateral 
fronto-nasal and naso-premaxillary sutures, is highly characteristic of birds, — an arrangement 
probably exceptionless. Two other horizontal prongs on each side, extensively distinct from 
the frontal process in most birds, but less separate from each other, run horizontally along the 
side and roof of the mouth for a variable distance. These horizontal prongs are an external or 
dentary process (fig. 80, dpx), forming the tomium (p. 104) of the bill, and reaching back to 
join the dentary part of the maxillary; and an internal or palatal process (fig. 80, ppx), run- 
ning along the commencement of the bony palate. With this latter the anterior ends of the 
palatal bones unite, — either on the side toward the mid-line of the beak, or between the palatal 
and dentary processes, as in a woodpecker (fig. 80). Great laminar expansions inward of these 
palatal parts of the premaxillaries roof the hard part of the mouth anteriorly, though there is 
usually a vacancy between the premaxillary hard palate and that formed farther back by the; 
maxillo-palatines and palatines. The posterior extremities at least of the frontal processes of 
the premaxillaries are commonly distinguishable from each other, as well as from the frontal j 
and nasal bones — in fact, these fronto-naso-premaxillary sutures are among the most per-l 
sistent of all. The divergence of the frontal fi*om the palatal and dentary processes bounds th(J 
external nostril in part, the circumscription of that orifice being completed by the prongs of thJ 
nasal bones. The superficies of the premaxillary bone, like that of the dentary piece of th(l 
lower jaw bone, is commonly sculptured with the impressions of the vessels and nerves whicM 
