The only cause of these exaggerations is a feature, striking it is true, which is presented by this cranial vault. In the Neanderthal man the frontal sinuses have an exceptional development, and the superciliary ridges, almost lost in the middle of the glabella, form a most strange protuberance above the orbit. This conformation has not failed to be compared to the _bony ridges_ which the anthropomorphous apes possess in the same place. Then, starting from this fact, it has been thought necessary to find in the rest of the cranium characters in harmony with this _simian feature_. Stress has been laid upon its slight elevation, the lengthened form, the projection of the occipital region, etc. With a little partiality, and by only comparing it with modern skulls, which are considered as normal, a separate species of being has been made of the Neanderthal man. By degrees, however, other crania equally fossil have been connected with this type. Indeed, in several parts of Europe those characters which were too hastily declared to be unique have been observed in dolmens in less ancient burial places, in historical persons, and even in individuals living at the present time. There was, then, no alternative but to conclude that the Neanderthal man belonged to a formation which was unquestionably human, to a _race_, certain features of which were merely exaggerated in his case. This race is none the less remarkable and perfectly characterized. In all individuals of the male sex we find a greater or less development of the superciliary prominences, which were so striking in the Neanderthal man. The low and narrow forehead appears still more receding in consequence of this contrast. The cranial vault is much flattened. Tolerably regular in its two anterior thirds, it rises towards the upper portion of the occiput, and is prolonged backwards. The entire skull is relatively narrow, and we have already seen that the cephalic index descends as low as 72. These bones are also remarkable for their thickness, which in the Eguisheim cranium reaches 11 millimetres (0·43 in.). Some of these features are modified in the female skull. The superciliary ridges disappear almost entirely. The occipital protuberance, and especially the prominence of its upper portion, are much less marked. The cephalic index rises one or two units, but the flattening of the vault and the other characters are persistent.