We learn from these calculations that, relatively to the cranium to which it belongs, the foramen magnum is placed more forward in the Negro than in the White, which is by no means the case in apes. These same calculations demonstrate the real difference which here distinguishes the two, that, namely, of the forward prolongation of the face. In drawing comparisons between men and apes, the _sphenoïdal angle_ discovered by M. Virchow, studied by M. Welker, and which, thanks to M. Broca, may be measured without making a section of the skull, presents special interest. It presents an inverse evolution in man, and the Quadrumana during growth. This may be seen from the annexed calculations borrowed from M. Welker:— MAN. 8 Infants 141° 10 Children from 10 to 15 years 137° 30 Adult Germans 134° ---- Difference -7° APES. Sajou, at birth 140° ” adult 174° ---- Difference +34° Orang., young 155° ” adult 172° ” old 174° ---- Difference +19° I have already insisted that facts of this nature are irreconcilable with those theories which attribute a more or less pithecoid ancestor to man. In discussing the cranial cavity, our special object is to supply the deficiency of information upon the volume and weight of the brain. Now, from this point of view, we may easily fall into error. The bony cabinet and its contents are developed, to a certain extent at least, independently. This is very clearly demonstrated by a fact which was observed by Gratiolet, and is too frequently forgotten. The subject is an infant in whom the cranium presented the normal conformation. The brain was, nevertheless, almost entirely wanting. In well-formed men the sinuses and coverings of the brain may very easily be more or less developed according to the individual or race, and influence the relative dimensions of the brain. Moreover, the exact measurement of the capacity of the cranium is attended by difficulties which have not yet been entirely surmounted. In spite of the improvements introduced by M. Broca in his method of measuring with shot, consecutive measurements of the same cranium by the same observer will vary considerably in the result.