(From aura, air, as being the medium of hearing). The ear. The ear is usually divided into the external and the internal. By the external is meant all that lies without the external orifice of the meatus auditorius in the os temporis; see Auricula. By the internal, all that lies within the cavity of this bone; the orifice of which is called cyar. For meatus auditorius, Tympanum, and Labyrinth, See Labyrinthus, etc.

The arteries of the external ear come anteriorly from the arteria temporalis, and posteriorly from the occipitalis. The veins are branches of the external jugulars. The portio dura of the auditory nerve having passed out of the cranium through the foramen stylo-mastoidaeum, gives off a branch, which runs up behind the ear, whence it sends off several filaments to the meatus and fore side of the ear. The second vertebral pair send also a branch to the ear, the ramifications of which communicate with those of the other branch from the portio dura.

The bones of hearing, called malleus, incus, orbicu-lnre, and stapes, are placed in the cavity of the tympanum, immediately on the inside of the membrana tym-pani. The malleus is joined by its handle to the membrana tympani, and its round head rests on the incus, the long leg of which rests on the os orbiculare, which is fixed to the fore part of the stapes, the sole of which rests on the hole called fenestra ovalis.

The use of the external ear is to collect sounds, and to render their impression on the other organs of hearing most perfect; this is evident from those who have their ears cut off being obliged to use a horn, or some means to assist them in hearing: all animals, as deer, hares, etc. whose ears have much motion, always direct them so as to meet the sound.

How hearing is effected, see Auditus and Sonus.

On the ears, see Cassebomius, Du Verney, Valsalva, Celsus, and Winslow's Anatomy. They treat either of the anatomy or the disorders of the ear.

Auris marina. Aurmar. A shell fish very common on the coast of Scotland, Guernsey, Normandy, etc. It is shaped like an ear, it adheres to rocks, and to render them eatable they are first boiled, then fried.