THE ANATOMY OF BIRDS.— OSTEOLOGY. 



179 



fegithognathous type ; it is frequently massive in that direction, and of endlessly varied con- 

 figuration. 



Saurognathism. — (Gr. a-avpos, sauros, a lizard; fig. 80). According to Huxley the 

 woodpeckers exliibit a •' degradation and simplification of tlie aegithognathous structure." The 

 peculiarities of the palate of these birds (including Picidce, PicumnidcB and lyngidce) are so 

 decided that Parker proposes to call them saurognatJious. 

 to make out, and may be understood best by 

 study of the accompanying figure, copied from 

 Parker. The maxillo-palatines, mxjo, are 

 very slight, not extending inward beyond the 

 outer margin of the palatines, and being some- 

 times quite rudimentary. In front of them, 

 an additional little palatal plate of the max- 

 illary, pmx, is developed. The vomers, v, are 

 delicate paired rods on each side of the median 

 line. The postero-external angle of the pala- 

 tine is either rounded off or obtuse-angled. 

 Where the broad main part of the palatine 

 suddenly narrows is developed an interpala- 

 tiue process, ipa. The ethino-palatine plates, 

 ejxi, or internal superior plates of the palatine, 

 which are of variable length, are connected 

 by the most marked medio -palatine t)ssifica- 

 tiiin, mpa, seen in the class of birds. Bridges 

 of bone are deposited along the inner borders 

 (if tlie palatines; such are the septo-maxil- 

 laries, smx, and other formations which, like 

 tlie medio-palatine, serve to bind the palate 

 lialves together. The nasal chambers are 

 unusually simple ; there are peculiarities of 

 tVi<' tympanic cavity and quadrate bone. 



" All these things being considered," 



says Parker, in conclusion, " it will Seem con- 

 tradictory now to assert the great uniformity 

 of tlie skulls of Birds, and indeed of Birds 

 Tlit-mselves. Yet so it is ; and the countless 

 mndifications that offer themselves for obser- 

 vation are gentle in the extreme. One form 

 is often seen to pass into another by almost 

 insensible gradations. ... In the rest of the 



Fig. 80. — Saurognathous skull of nestling Picus 

 minor, x 4 diameters, after Parker. Px, premaxillary : 

 dpx, its dentary process; ppx, its palatal process; sn, 

 septo-nasal ; pa, palatine ; pmx, peculiar palatal plate of 

 maxillary of a woodpecker; «/; nasal turbinal; mx, 

 maxillary; ipa, interpalatal spur of palatine bone; mxp, 

 rudimentary maxillo-palatine, scarcely reaching palatine; 

 smx, septo-maxillary, in several pieces ; r, right vomer, 

 its fellow opposite ; pe, lower border of perpendicular plate 

 of ethmoid, between vomers ; epa, ethmoidal (inner) 

 plate of palatine; mpa, medio-palatine ; pg, pterygoid; t, 

 foramen for internal carotid ; 8, for vagus nerve ; 9, for 

 hypo-glossal nerve. 



Birds' organization abundant evidence of tl 

 same specialization will be seen. The mind fails to desire more beauty or to contemplate more 

 ex((uisite adaptations. An almost infinite variety of Vertebrate life is to be found in this class. 

 Of its members some dig and bury their germs, which rise again in full plumage, whilst others 

 watch and incessantly feed their tender brood in the shady covert or ' on the crags of the rock 

 and the strong place.' In locomotion some walk, others run, or they may wade, swim, plunge, 

 or dive, whilst most of them 'fly in the open firmament of heaven.'" {Ency. Brit. 9th ed. 

 Art. Birds, p. 717.) 



