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
The Anvil or the Hammer watched by 4.58 million viewers, with a 1.5 rating among 18-49 adults. With Live+7 DVR viewing factored in, the episode had an overall rating of 7.23 million viewers, and a 2.6 in the 18–49 demographic. "The Anvil or the Hammer" received mixed-to-positive reviews. The episode received a rating of 60% with an average score of 6.7 out of 10 on the review aggregator Rotten Tomatoes, with the site's consensus stating: "Though the plot twist was surprising, 'The Anvil or the Hammer' disregarded "Gotham"s own history, muddying up the narrative with a nonsensical story." Matt Fowler of IGN gave the episode