The fornix is an arch-shaped bundle of axons in the cerebrum. It is located below the corpus callosum and separated from it in front by the the septum pallucidum. It transmits signals from the hippocampus to the mammillary bodies and septal nuclei. The fornix begins in the hippocampus on each side of the brain. The left and right sides are each called the crux of the fornix. The bundle of axons come together in the midline of the brain and form the body of the fornix. The body of the fornix travels backward to divide again near the anterior commissure.