3.) The middle ear communicates with the mouth by the Eustachian tubes, which pass between the basisphenoid and basioccipital bones, and unite upon the ventral side of the sphenoid, a little behind its articulation with the pterygoids, where they open into the mouth cavity by a short membranous duct.
The sternum has no keel, and ossifies from lateral and paired centres only; the axes of the scapula and cora.coid have the same general direction; certain of the cranial bones have characters very unlike those possessed by the next order - the vomer, for example, being broad posteriorly and generally intervening between the basisphenoidal rostrum and the palatals and pterygoids; the barbs of the feathers are disconnected; there is no syrinx or inferior larynx; and the diaphragm is better developed than in other birds.'
In them the vomer, however variable, always tapers to a point anteriorly, while behind it includes the basisphenoidal rostrum between the palatals; but neither these nor the pterygoids are borne by its posterior divergent ends.
Without a mental groove; the ends of the pterygoids are free, not reaching the quadrate.
Sharp, recurved teeth are carried by the mandibles, the pterygoids, palatines, maxillaries, and in the Pythoninae by the premaxillaries also.
Pterygoids connected with the quadrates which are carried by the squamosals, and these are loosely attached to the skull.
- The pterygoids are widely separated from the quadrates, not reaching beyond the level of the occipital condyle.
There are also teeth on the palatines, anterior portion of the pterygoids, and on the short dentaries.
The pterygoids are delicate slender slips of bone attached to the hinder border of the palatines, and supported externally by, and generally welded with, the rough pterygoid plates of the alisphenoid, with no pterygoid fossa between.
Simultaneously on the vomers, the palatines, Rsvc, Lsvc, right the pterygoids and the parasphenoid in and left supesome of the Stegocephalia (Dawsonia, Seeleya, rior cavae.
Dontinae and Desmognathinae), on the vomers, Ao, Left aortic Pterygoids and parasphenoid (some Pelobates), arch.