1-W: MAMMALIAN DENTITION 



with the apex of the crown by a low ridge. The upper pre- 

 molars have quite massive crowns and are subequal in size. In 

 the mandible the premolars present a rounded and obliquely 

 sloping labial surface. Their main cusp lies in the vertical 

 axis of the tooth and in consequence the occlusal surface is 

 directed obliquely inwards. The second premolar is especially 

 massive and molariform through the development of a posterior 

 moiety. The molars again are powerful teeth with long almost 

 parallel and unfused roots ; the third is not yet fully erupted. 

 Both first and second maxillary molars present a typical tri- 

 gon with an oblique ridge and in addition a well-developed 

 hypocone. They are subequal in size with the autero-posterior 

 dimension almost equal to the transverse. The third molar 

 crown, smaller in size, does not show the cusps so clearly as 

 the more anterior teeth but it also possesses a hypocone. The 

 teeth are obliquely rhomboidal and except in the third molar 

 the corners are but slightly rounded off. The lower molars are 

 typically human in the cruciform arrangement of their fur- 

 rows. Each possesses a hypoconulid but displays advanced 

 characters in certain respects. The transverse ridge between 

 protoconid and metaconid is quite pronounced. The occlusal 

 surface is narroAver than the crown itself. The hypoconulid 

 tends to be subdivided. In addition to these advanced features 

 of individual teeth the purely human character of an angle 

 between the antero-posterior axis of the first lower molar and 

 that of the second is present. All the teeth are well rounded 

 and are subequal in antero-posterior length. An interesting 

 feature reminiscent of the Eocene Primates and found also as 

 a small tubercle in the Gorilla molar is a small sixth cusp be- 

 tween the metaconid and the entoconid. 



Having drawn attention to the main distinctive marks of the 

 Aurignacian and Xeandertal dentitions it may be asked if the 

 latter shows in reality any features not to be observed in some 

 at least of modern crania. There is no doubt that every fea- 

 ture discussed can also be found in any fair-sized collection of 

 recent skulls although perhaps the extent and blending of the 



