THE ANATOMY OF BIRDS. — OSTEOLOGY. 
171 
Line birds (Peristeromorphce of Huxley's arrangement) : maxillo-palatines elongate and 
spongy; basipterygoid processes narrow, but prominent, (b) The gallinaceous birds {Alec- 
toromorphce) : maxillo-palatines varying greatly in size, but always lamellar ; palatines long 
and narrow, with rounded off postero-exterual angles; basipterygoid processes oval, flattened, 
sessile upon the rostrum, articulating with the pterygoids, (c) The penguins {Sphenisco- 
morphce) : maxillo-palatines concavo-convex and lamellar; no basipterygoid processes; ptery- 
goids flattened, {d) In the gulls, petrels, loons, grebes, 
and auks, constituting the Cecomorphce of Huxley, the 
maxillo-palatines are usually lamellar and concavo- 
convex, but may be spongy, tumid, and closely approx- 
imated to the vomer ; and basipterygoid processes are 
absent or present, (e) In the cranes, rails, and their 
allies {GeranomorphcB) J the maxillo-palatines are con- 
cavo-convex and lamellar, and basipterygoid processes 
are usually absent. (/). In the plover-snipe group, 
or limicoline GrallcB {Charadriomorphoi) j the maxillo- 
palatines are always concavo-convex and lamellar ; the 
basipterygoid processes narrow and prominent. Except- 
ing perhaps group d, which does not hang together so 
well, the schizognathous groups here noted correspond 
very closely with recognized orders or suborders of birds; 
in all of them, the maxillo-palatines are perfectly dis- 
tinct from one another and from the vomer, and the 
latter is slender and usually pointed. There are plenty 
of other birds in which the former factor in the case 
obtains ; but in these the vomer is broad and usually 
truncate in front (see JEgithognathism, beyond). 
Desmognathism (Gr. 8e(r/i6y, desmos, a bond) is 
exhibited in one or another style by those swimming 
and wading birds which are not schizognathous, by 
the birds of prey, and various non-passerine perching 
birds. It does not fadge so well as any other one of 
the palatal types of structure with recognized groups of 
birds based on other considerations. In the '^bound- 
palate " type, the vomer is either abortive, or so small 
that it disappears ; when existing it is usually slender 
and tapers to a point in front; the maxillo-palatines 
are united across the median line, either directly or by 
means of ossifications in the nasal septum ; the posterior 
ends of the palatines and the anterior ends of the ptery- 
goids articulate directly with the rostrum (as in schizo- 
gnathism). This type is simply and perfectly exhibited by a duck (fig. 78) in which the 
maxillo-palatine is a broad flat plate united with its fellow in mid-line ; the oval sessile basi- 
pterygoid facets are far forward, opposite the very ends of the pterygoids. In the flamingo, 
ibis, spoon-bill, stork, heron, the united maxillo-palatines are tumid and spongy, filling the 
base of the beak ; basipterygoids are wanting (rudimentary in the flamingo). In totipalmate 
swimmers (pelican, cormorant), desmognathism is carried to an extreme by union of the palate 
bones also across the mid-line; the general arrangement is as before. The birds of prey 
exhibit several special conditions of desmognathism. The parrots are another case ; among 
Fig. 78 — Desmognatlious skull of mal- 
lard duck, Anas hoscas, nat. size, from 
nature, by Dr. R. W- Shufeldt, U. S. A. 
Letters as before. 
