THE ANATOMY OF BIRDS. — OSTEOLOGY. 
173 
segithognathous type 
figuration. 
it is frequently massive in that direction, and of endlessly varied con- 
Saurognathism. — (Gr. aavpos, sauros, a lizard; fig. 80). According to Huxley the 
woodpeckers exhibit a degradation and simplification of the segithognathous structure." The 
peculiarities of the palate of these birds (including Picidce, PicumnidcB and lyngidce) are so 
decided that Parker proposes to call them saurognathoiis 
to make out, and may be understood best by 
study of the accompanying figure, copied from 
Parker. The maxillo-palatines, mxp, 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- 
tine process, ipa. The ethmo-palatine plates, 
epa, or internal superior plates of the palatine, 
which are of variable length, are connected 
by the most marked medio -palatine ossifica- 
tion, mpa, seen in the class of birds. Bridges 
of bone are deposited along the inner borders 
of the palatines; such are the septo-maxil- 
laries, smx, and other formations which, like 
the medio-palatine, serve to bind the palate 
halves together. The nasal chambers are 
unusually simple ; there are peculiarities of 
the tympanic cavity and quadrate bone. 
The structure is very difficult 
All these things being considered," 
says Parker, in conclusion, it will seem con- 
tradictory now to assert the great uniformity 
of the skulls of Birds, and indeed of Birds 
themselves. Yet so it is ; and the countless 
modifications 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 
Birds' organization abundant evidence of the 
same specialization will be seen. The mind fails to desire more beauty or to contemplate more 
exquisite 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.) 
EiG. 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; nf, nasal turbinal; mx, 
maxillary ; ipa, interpalatal spur of palatine bone ; vixp, 
rudimentary maxillo-palatine, scarcely reaching palatine ; 
smx, septo-maxillary, in several pieces ; v, 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 ; i, 
foramen for internal carotid ; 8, for vagus nerve ; 9, for 
liypo-glossal nerve. 
