The incus or anvil is the anvil-shaped small bone or ossicle in the middle ear. It connects the malleus to the stapes. It was first described by Alessandro Achillin of Bologna. The incus transmits sound vibrations from the malleus to the stapes. The incus only exists in mammals, and is derived from a reptilian upper jaw bone, the quadrate bone. Embryologically it is derived from the first pharyngeal arch along with the rest of the bones of mastication, such as the maxilla and mandible. [WP,unvetted]. [ http://en.wikipedia.org/wiki/Incus ]