THE HUMAN DENTITION 139 



diameters of the crown are much more nearly alike than in 

 Anthropoids and as a result of this the two inner cusps are 

 drawn more closely together while the furrow between the 

 labial surfaces of protoconid and hypoconid is very slightly 

 marked. As a result of the altered relationships of the cusps 

 the furrows upon the occlusal surface, instead of presenting 

 an appearance similar to that of the molars in Gorilla, are ar- 

 ranged in cruciform pattern. The very small metaconid does 

 not come into contact at all with the hypoconid and the well- 

 developed entoconid encroaches upon the area of the crown 

 occupied in the Anthropoids by the metaconid, so that all four 

 principal cusps meet at the central point of the occlusal sur- 

 face. The groove between metaconid and entoconid is continu- 

 ous in a transverse line with that separating the protoconid 

 from the hypoconid, whereas in Anthropoids it is contin- 

 uous obliquely backward with the furrow between the hypo- 

 conid and the hypoconulid. Another consequence of the rela- 

 tively large cusps on the talonid is the increase in transverse 

 breadth of the posterior moiety of the tooth over the anterior 

 part. The hypoconulid is not displaced so far laterally as in 

 Anthropoids. In addition to the foregoing facts relating to the 

 appearance of the individual teeth themselves, essentially hu- 

 man characters are found in the general arrangement of the 

 cheek teeth in the jaw. Insteacjfrof the premolars and molars 

 forming either a straight line antero-posteriorly or an arch 

 very slightly concave laterally, they are set in a curve most 

 pronounced anteriorly indeed but concave throughout towards 

 the tongue. The antero-posterior axis of the first molar is set 

 at an angle with that of the second, a feature which is distinc- 

 tively human though more pronounced in some mandibles than 

 in others. 



The conspicuous even wearing of all the teeth causes them 

 to resemble those of more recent Man in whom the teeth are 

 worn by the mastication of food prepared from cereals ground 

 between gritty mill-stones and suggests that Heidelberg Man 

 was already in the habit of masticating cakes prepared from 



