266 THE DENTAL SYSTEM OF THE PRIMATES [SECT. A 



cusps are of frequent occurrence in the molar crowns of the 

 Hominidae and of the higher Primates in general. 



But the molar teeth may also present anomalous conditions of 

 their roots. In the Hominidae, additional roots are as likely to 

 be found in the lower as in the upper molars. The number of 

 accessory roots is variable, and in the third lower molar as many 

 as three have been recorded (making a total of five roots). The 

 socket for the third lower molar tooth in the celebrated Naulette 

 jaw is said to indicate the former presence of a tooth with five 

 roots. But this statement is not confirmed by the examination 

 of a cast of this mandible (in the Cambridge Collection), nor is 

 it supported by the photograph recently published by Dr Keith 

 (Proc. Roy. Soc. Medicine, Odont. Sect., Vol. vi. 1913). 



Accessory molar roots in the other Primates are probably rare, 

 for records are inaccessible or non-existent. 



Reference must be made here to the remarkable and aberrant 

 forms presented by some (but not all) of the prehistoric human 

 teeth from the site at Krapina in Croatia (Fig. 198). 



The outstanding feature is the fusion of the roots in the molar 

 teeth. The combined roots form a pillar supporting the crown of 

 the tooth. At the base of the pillar the extremities of the roots 

 are in some examples indicated by small pointed projections. 

 Between these projections, a plate-like or saucer-shaped disc (Wur- 

 zeldeckel) completes the fusion of the roots, and is very evident in 

 a vertical section of the tooth (Fig. 198 K.o.). Teeth so anomalous 

 as these offer a striking contrast to all other molar teeth in the 

 Primates. As a rule the roots of the molar teeth in this group of 

 mammals are distinctly divergent from one another. 



Thus the Krapina type differs from the normal molar much as 

 docs the molar of the Ox from that of the Dog. For this reason, 

 Professor Keith proposes to describe the Krapina molars (thus 

 characterized) as "taurodont," while the normal type is designated 

 "cynodont 1 ." The same writer points out that in the taurodont 

 molars, the pulp-cavity extends within the gum or alveolar margin 

 of the jaw, whereas normally the pulp-cavity stands clear of that 



1 Proceedings of the Royal Academy of Medicine, Vol. vi. Odontological Section, 

 1913. 



