The two Melville characters referenced in the crossword solutions are Ahab and Omoo. Ahab is a character from Herman Melville's novel Moby-Dick, which follows the story of a whaling voyage. Ahab is the captain of the ship, and his obsession with hunting down a white whale drives the plot of the novel. Omoo is a character from Melville's novel Omoo: A Narrative of Adventures in the South Seas, which follows the story of a sailor who is shipwrecked and then joins a mutiny. Omoo is a Tahitian native who helps the sailor survive his ordeal.