3. There is a pair of deep concavities on the posterior margin of the skull-one behind each eye. (A picture of the skull of Seymouria is shown below, indicating what I'm talking about.) a. What is this structure? Incifive Foramen b. With what structure in jawed fishes is it homologous? c. What bony structure woud project through it? (You can't see it on the cast or in the picture. Hintit's primary role is in hearing.).