THE TEETH OF PRIMATES. 413 



surface is marked by that finely wrinkled pattern which is 

 common to all the unworn teeth of the orang. One is 

 struck by the great backward elongation of the jaws, by 

 their squareness, by the parallelism of the two sidea 

 which converge slightly at the back, and by the large size 

 of the teeth in proportion to the bulk of the whole animal. 



The large size of the canines being in a measure a sexual 

 character, is, as is so often the case, not very noticeable in 

 the young animal : the two acompanying illustrations of 

 a, young and an adult male orang may serve to show this, as 

 well as some other differences developed by age. 



The differences which serve to distinguish the dentition 

 of the most anthropomorphic apes from that of man are 

 mainly these. Relatively to the size of the cranium, and of 

 the whole creature, the teeth and jaws are very much larger 

 in all their dimensions ; hence the creatures are progna- 

 thous, and the facial angle small, even when compared 

 with the jaws and cranium of an idiot. As might be ex- 

 pected this difference is not so great in the young as in the 

 adult animal. 



In place of the teeth being arranged in a sweeping curve, 

 the jaws are squarish, the incisors being arranged in some- 

 thing approaching to a straight line between the two great 

 outstanding canines, behind which the premolar and molar 

 series run in straight lines, converging somewhat as they go 

 backward. There is a " diastema " ( J ) or interval in front of 

 the upper canine, into which the point of the lower canine 

 passes, when the mouth is closed. Both the greater square- 

 ness of the jaws, and the existence of a diastema, are direct 

 results of the great size of the canines, and are consequently 

 not marked in young specimens. 



The upper premolars are implanted by three roots, the 



(*) Fomething approaching to a diastema is said to have been observed 

 by Vogt and Broca in early European skulls. 



