Middle ear to sounds of higher frequency, because these are better taken up by the inner ear (which also responds to higher frequencies than those of non-mammals). The malleus, or "hammer", evolved from the articular bone of the lower jaw, and the incus, or "anvil", from the quadrate. In other vertebrates, these bones form the primary jaw joint, but the expansion of the dentary bone in mammals led to the evolution of an entirely new jaw joint, freeing up the old joint to become part of the ear. For a period of time, both jaw joints existed together, one medially and one
Anvil are used today. There is a growing interest in re-enacting this "ancient tradition" in the US, which has now spread to England. The African Methodist Episcopal Church (AME) has the anvil in its coat of arms. The AME's first services were held in a blacksmith's shop. A typical metalworker's anvil, with horn at one end and flat face at the other, is a standard prop for cartoon gags, as the epitome of a heavy and clumsy object that is perfect for dropping onto a villain. This visual metaphor is common, for example, in Warner Brothers' "Looney Tunes" and "Merrie Melodies"