164 GENEBAL OBNITHOLOGY. 



external lamina. It is well shown in a Passerine or Kaptorial bird, where the postero-external 

 angle (between the outer border and the posterior end) of the palatal is well-marked, or may 

 be acutely piroduced ; there is no such lamina in a fowl, where the palatals are for the most 

 part slender and rod-hke. An internal, more or less vertically produced, plate to make the 

 mid-line rostral or vomerine connection is the SKperior internal lamina, or niedio-palaiine 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 tlie 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 M'here 

 the superior internal and external lamina; 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-extemal angles of the palatal (formed by the external 

 lamina I, even when much produced, may not reach as far back as opposite tlie pterygo-palatine 

 articulation ; or they may surpass these Umits, and when they do, snob 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-pialatines. The inner posterior process, by which the palatine is articu- 

 hited with the pterygoid, is ixs, pterygoid process. 



The Premaxillary Bones (figs. ()2 ; 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, theii' 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, //(e premaxillary. Each is a triradiatc or 3-pronged bone; one upper prong, the most 

 distinct, called the nasrd or frontal process, forms with its fellow the culmen (p. 101, fig. 2C, h) 

 of the bill. These processes, side by side, run (dear up to t\m 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 higldy characteristic of birds, — an arrangement 

 jirobiibly 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 f>f the mouth for a variable distance. These horizontal jirongs are an external or 

 dentarij process (fig. 80, dpx), forming the tomimn (p. 101) of the bill, and reaching back to 

 join the dcutary part of the maxillary; and an internal or palatad process (tig. 80, l^px"), 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 thendd-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 (]f the prernaxillaries roof the hard jiart of tlie mouth anteriorly, though there is 

 usually a vacancy between the premaxillary hard palate and that formed fartlier b:ick by the 

 maxilld-palatines and palatines. Tlie posterior extremities at least of the fnnital processes of 

 tlie prernaxillaries are commonly distinguishable from each other, as well as frcnii tlie frontal 

 aud nasal bones — in fact, these fronto-naso-jiremaxillary sutures are among the most per- 

 sistent of all. The divei'gence of the frontal from the ]ialatal and dentary processes bounds the 

 external nostril in part, the circumscription of that orifice being completed by the prongs of the 

 nasal bones. The superficies of the premaxillary bone, like that of the dentarv piece of the 

 lower jaw bone, is commonly sculptured with the impressions of the vessels and nerves which 



