The cerebrum is the brain's largest component, consisting of two cerebral hemispheres joined by the corpus callosum, a mass of white matter. Each cerebral hemisphere extends from the frontal to occipital bones over the anterior and middle cranial fossae, as well as posteriorly above the tentorium cerebelli. A deep gap, the longitudinal fissure, separates the hemispheres, through which the falx cerebri projects. The hippocampus is a key component of human and other animal brains. The hippocampus is a component of the limbic system that aids in the consolidation of information from short-term to long-term memory as well as spatial memory. Hippocampi are two structures in the brain that are found on opposite sides of the brain in humans and other mammals. The hippocampus is C-shaped in frontal section, and its outline resembles a Ram's horn, hence the name Ram's horn. It is also called Ammon’s Horn after an Egyptian deity with a ram’s head. Its anterior extremity is elongated, with a few grooves and ridges between them. It's called pes hippocampi (pes = foot) because it looks like an animal's paw. The hippocampus narrows as it travels backward, eventually ending beneath the splenium of the corpus callosum.