"The two cerebral hemispheres are asymmetrical; in the region where the parieto-occipital fissure is situated on the left hemisphere, the two hemispheres diverge from each other and form an edge which curves outward and backward, so that the cerebellum remains uncovered. On the lower surface of the frontal lobes there exists a strongly marked ethmoidal prominence. Neither of the fissures of Sylvius is quite closed, the left less so than the right; the operculum is but slightly developed, and the island of Reil lies with its fissures almost entirely uncovered. This conformation reminds us throughout of the brain of the anthropoid apes. The two _sulci centrales sive fissurae Rolandi_ run straight to the border of the hemisphere, less deeply impressed than is normally the case, without forming an angle with each other. Very strongly and deeply impressed _sulci praecentrales_ seem to serve as substitutes for them. The _sulcus interparietalis,_ which begins farther outward than in the ordinary human being, receives the _sulcus parieto-occipitalis_--a structure in conformity with the typical brain of the ape. The _sulcus occipitalis transversus_, which is generally lightly stamped in man, extends here as a deep fissure across over the occipital lobe, thus producing a so-called simian fissure, and the posterior part of the occipital lobe has the appearance of an operculum. The _fissura calcarina_ has its origin directly on the surface of the occipital lobe, does not receive until late the _fissura parieto-occipitalis_, and goes directly, on the right side, into the _fissura hippocampi_. This abnormal structure also is typical for the brain of the ape. "The _gyrus occipitalis primus_ is separated from the upper parietal lobe by the _sulcus parieto-occipitalis_, a formation that, according to Gratiolet, exists in many apes. The _gyrus temporalis superior_ is greatly reduced on both sides, and has an average breadth of only five millimetres; it is the one peculiarity that recalls emphatically the brain of the chimpanzee, which always has this reduced upper temporal convolution. "We have here, then, a brain that scarcely deviates from the normal brain in volume, that possesses all the convolutions and fissures, seeming, perhaps, richer than the average brain in convolutions, and that is in every respect differentiated; and notwithstanding all this it approximates, in its whole structure, to the simian rather than to the human type. Had the brain been placed before me without my knowing its origin, I should have been perfectly justified in assigning this brain to an anthropoid ape standing somewhat nearer to man than does the chimpanzee." No second case of this sort has thus far been observed. C.