. Evidence as to man's place in nature . ons, and a ridge crosses the crown ob-liquely, from the inner, anterior, cusp to the outer, posteriorcusp (Fig. 18 m). The anterior lower molars have five cusps,three external and two internal. The premolars have twocusps, one internal and one external, of which the outer isthe higher. In all these respects the dentition of the Gorilla may bedescribed in the same terms as that of Man; but in othermatters it exhibits many and important differences (Fig. 18). Thus the teeth of man constitute a regular and even,series—without any break and without any mark
. Evidence as to man's place in nature . ons, and a ridge crosses the crown ob-liquely, from the inner, anterior, cusp to the outer, posteriorcusp (Fig. 18 m). The anterior lower molars have five cusps,three external and two internal. The premolars have twocusps, one internal and one external, of which the outer isthe higher. In all these respects the dentition of the Gorilla may bedescribed in the same terms as that of Man; but in othermatters it exhibits many and important differences (Fig. 18). Thus the teeth of man constitute a regular and even,series—without any break and without any marked projec-tion of one tooth above the level of the rest; a peculiaritywhich, as Cuvier long ago showed, is shared by no other 82 mammal save one—as different a creature from man as canwell be imagined—namely, the long extinct teeth of the Gorilla, on the contrary, exhibit a break, orinterval, termed the diastema, in both jaws: in front of theeye-tooth, or between it and the outer incisor, in the upper ^ Gcri llcL. CJieircmys. Fig. 18.—Lateral views, of the same length, of the upper jaws of variousPrimates. ?, incisors ; c, canines ; pm, premolars ; m, molars. A line is drawnthrough the first molar of Man, Gorilla, Cynocephalus, and Cebus, and thegrinding surface of the second molar is shown in each, its anterior and internalangle being just above the m of»». 83 jaw; beliiud the eye-tootli, or between it and the front falsemolar, in the lower jaw. Into this break in the series^ ineach jaw, fits the canine of the opposite jaw; the size of theeye-tooth in the Gorilla being so great that it projects, like atusk, far beyond the general level of the other teeth. Theroots of the false molar teeth of the Gorilla, again, are morecomplex than in Alan, and the proportional size of the molars isdifferent. The Gorilla has the crown of the hindmost grinderof the lower jaw more complex, and the order of eruption ofthe permanent teeth is different; the permanent can
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