Eo, Opisthotic. prp, Pterygoid process of sphe eu, Eustachian tube.
Eu, Eustachian tube.
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.
Here may be mentioned the guttural pouches, large airsacs from the Eustachian tubes, and lying behind the upper part of the pharynx, the function of which is also not understood.
Aglossa, - Eustachian tubes united into a single ostium pharyngeum; no tongue.
Phaneroglossa, - Eustachian tubes separated; tongue present.