xxnr. 7 



TEETH OF PRIMATES 



619 



A B 



CEBUS MACACA 



Fig. 396. Tooth rows of New World and Old World monkeys. (After 

 Le Gros Clark.) 



Tarsius. Amphipibhecus. Parapibhecus. Proconsul. Cercopibhecus 

 P a <^ meb. ^^ spr. 



FlG. 397. Diagram of the right lower molar cusp pattern in some Primates, to show the 

 presumed evolutionary stages in the development of the cusp pattern. Tarsius shows the 

 primitive (tribosphenic) type. The paraconid is involved in the formation of the trigonid. 

 *Amphipithecus shows the paraconid undergoing reduction while the talonid and trigonid 

 portions of the crown are at the same level. *Parapithecus: the paraconid has completely 

 disappeared, the talonid bears the hypoconid, the entoconid, and a relatively well- 

 developed hypoconulid; the trigonid portion bears the metaconid and protoconid. 

 *Proconsul: the five cusps are more or less equally developed and separated by a charac- 

 teristic pattern of intervening grooves. Cercopithecus shows the characteristic bilophodont 

 pattern, with transverse ridges. 



ent. entoconid; hid. hypoconulid; hy. hypoconid; met. metaconid; pa. paraconid; pr. 

 protoconid. (After Le Gros Clark.) 



monkeys have become terrestrial (baboons). The pollex and hallux are 

 opposable and the digits all carry nails. The hands and feet are used 

 for feeding as well as for locomotion. 



The characteristic of the tooth row is a tendency to shortening, 

 presumably connected with the shortening of the face. There are three 

 premolars in the earlier Anthropoidea, later reduced to two (Fig. 383). 

 In the line leading to man there is a tendency to still further reduction, 

 with the last molar becoming smaller than the others. The cusp- 

 pattern is tritubercular in earlier anthropoids, but later the molars 

 become square and have four or more bunodont cusps in higher 



