As soon as Alteria had brought to an end her long and interesting story the Signora bade her at once to set forth her enigma, and she, smiling pleasantly, obeyed the command. Far from this our land doth dwell One who by turns is fair or fell; Springing from a twofold root, One part woman, one part brute. Now like beauty’s fairest jewel, Now a monster fierce and cruel. Sweetest song on vocal breath, To lead men down to shameful death. Alteria’s most fitting and noteworthy enigma was answered in divers fashion by the listeners, some giving one interpretation of it and some another, but not one of them came upon its exact meaning. Therefore, when the fair Alteria saw there was little chance of anyone finding the true answer, she said: “Ladies and gentlemen, the real subject of my enigma is the fascinating Siren who is fabled to dwell in the deep sea. She is very fair to look upon, for her head and breast and body and arms are those of a beautiful damsel, but all the rest of her form is scaly like a fish, and in her nature she is cunning and cruel. She sings so sweetly that the mariners, when they hear her song, are soothed to slumber, and while they sleep she drowns them in the sea.” When the listeners heard this clever and subtle solution given by Alteria, they praised it warmly with one accord, declaring the while that it was most ingenious. And she, smiling with pleasure and gratitude, rose from her chair and thanked them for their kindness in thus lending their attention to her story. As soon as she had taken her seat, the Signora made a sign to Eritrea to follow in the due order with her story, and she, blushing like a morning rose, began it in these words. THE FIFTH FABLE. Isotta, the wife of Lucaferro Albani of Bergamo, devises how she may trick Travaglino the cowherd of her brother Emilliano and thereby show him to be a liar, but she loses her husband’s farm and returns home worsted in her attempt, and bringing with her a bull’s head with gilded horns.