is well shown in some famous human mandibles which undoubtedly belonged to individuals of the oldest palæolithic race hitherto known in Europe, as, for example, those of Spy and Naulette (Figs, 1 and 3). Not only so, but among neolithic and some European races of the present day these back molars, or wisdom teeth, make their appearance at a later date in the individual's life than in the earlier races, so that they seem to be on the high way to become vestigial organs. The lessening of the dental portion of the jaws Mr Darwin attributed to "civilised men habitually feeding on soft cooked food, and thus using their jaws less."
Another peculiarity of civilised races is the greater prominence of the chin, a feature which may also be a result of the retrocession of the facial bones, as the shortening of the alveolar ridges would cause the teeth to assume a more upright setting in their sockets. But whatever the precise cause may have been, there can be no doubt that the gradual formation of the chin has a striking parallelism with the progressive stages of man's intellectual development ever since he diverged from the common stem line from which he and the anthropoid apes have descended. In support of this view the eminent French anthropologist, Paul Broca, exhibited a drawing at a meeting of the International Congress of Anthropology and Prehistoric Archæology, held in Paris as early as 1867 (Comptes rendus, p. 399), which shows sectional examples of the chin of a chimpanzee and of various races found in prehistoric deposits, in comparison with that of a modern Parisian (Fig. 4). Also, Professor Albert Gaudry, at a subsequent meeting of the same congress, held at Monaco in 1906, exhibited the annexed sketch (Fig. 5) (ibid., vol. ii., p. 374), showing the comparative development of the chin of a modern Frenchman, of a young man of the Race de Grimaldi found in one of the caves of Mentone, and of a fossil monkey (Dryopithecus). A careful study of these illustrations cannot fail to be of the highest interest to all students of human anthropology. Since Paul Broca's time a number of other human mandibles have been discovered, corroborating the above concurrent parallelism between the evolution of the chin and the orthognathism of modern civilised races. (See Figs. 39, 41, 59.)
