This section, taken from a rabbit’s brain, shows the real nature of the hippocampal formation. It consists of a strip of cortex which is inrolled so as to form a bulge into the cavity of the lateral ventricle (V). This bulge is the hippocampus (H). Its cells are disposed in a very marrow compact stratum. The invagination of the hippocampal cortex takes place along the line of the hippocampal fissure (F). Towards the margin of the choroidal fissure, the hippocampal cortex gives way to the dentate gyrus (D) which is also composed of a narrow densely-packed layer of cells. At its other margin the hippocampus becomes continuous with the general cortex of the cerebral hemisphere (S). The photograph is at a magnification of X 36.

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