Vol. 70.] AND ASSOCIATED MAMMALIAN REMAINS. 91 



permanent canine, the outer (labial) face of the crown is com- 

 paratively narrow and deep, and is not continued in a gradual 

 curve round the posterior (lateral interstitial) face to the same 

 extent as in the fossil tooth. The milk-canine of Man, how- 

 ever, may be much more satisfactorily compared. In this tooth 

 the gently-convex outer (labial) face of the acuminate crown 

 (PI. XV, fig. 6<?) is relatively wider than in the permanent canine, 

 and gradually curves round to the posterior (lateral-interstitial) 

 face, exactly as in the fossil (PI. XV, figs. 2d & 6<7) ; while the 

 inner (lingual) face (fig. 6 b) is distinctly concave, and, if its 

 enamel were removed, would correspond very closely with the 

 worn face of the latter specimen (fig. 2 b). Seen from the flattened 

 anterior (median interstitial) face (PL XV, figs. 2 c & 6 c), these two 

 canines appear to be remarkably similar in shape, although, as might 

 be expected, the root is somewhat the shorter in the milk-tooth. 

 In all the existing Apes, and in the extinct Dry op iih ecus, the 

 permanent loAver canine is more conical than that of Eoantliropus, 

 with a more extensive production inwards of the base of the crown 

 on the lingmal side. It also appears to be usually larger and stouter 

 in proportion to the size of the jaw. The crown of the milk- 

 canine in the Apes, however, like that in Man, is much more 

 compressed, with a concave inner (lingual) face and a gently- 

 convex outer (labial) face, so that it closely approaches the fossil 

 in shape (PI. XV, figs. 8 a-8 d) : the only noteworthy difference 

 being that, in the Apes, there is already the characteristic small 

 produced heel or ledge at the base of the crown, at the hinder 

 (median-interstitial) end of the inner (Ungual) face. 



It results, therefore, from these comparisons that, among known 

 Upper Tertiary and Recent Anthropoids, the permanent lower 

 canine of JLoantliropus agrees more closely in shape with the milk- 

 canine both of Man and of the Apes than with the corresponding 

 permanent tooth in either of these groups. It is also obvious 

 that the resemblance is greater between JSoanthropns and Homo 

 than between the former and any known genus of Apes. In other 

 words, the permanent tooth of the extinct Eoantlrropus is almost 

 identical in shape with the temporary milk-tooth of the existing 

 Homo. Hence it forms another illustration of the well-known 

 law in mammalian palaeontology, that the permanent teeth of an 

 ancestral race agree more closely in pattern with the milk-teeth 

 than with the permanent teeth of its modified descendants. 



In this connexion, it is interesting to add that even in Homo 

 sapiens, if the base of the crown of the canine were raised in 

 the gum to the same level as that of the adjacent teeth, its apex 

 would frequently project well above the rest of the dental series. 

 The relatively large size and depth in the milk-dentition is espe- 

 cially well seen in a preparation in the Central Hall of the British 

 Museum (Natural History) ; see PI. XV, fig. 7. 



For valuable help in making these studies, I have again to 

 thank Mr. W. P. Pvcraft and Prof. Arthur S. Underwood. 



