ORDINAL TYl'KS OF MOLARS: I'l; I MATKS 



157 



PRIMATES. 



Cope's contention us to the tritubercular origin of the teeth of 

 Primates rested upon the strongest possible proofs both from com- 

 parative zoology and from pakeontology. The tri tubercular pattern 

 is still the prevailing one among the Lemuroidea, while the Antbropoidea 



A I 



B 



C 



c . p. 3 P- 



c. P-3 p.4 



V m : > m, 2 m-3 



FIG. 1:27. Jaws of American Eocene Primates, etc., natural sixo. 



A. Pelycodus tutus, family Notharctidae, order Primates. 



13. Iliiniii:l,ix /mulus, probably an Insectivore. 



''. ATiaptomorphus mulug, analogous to Tarsius. 



D. Microsyops sp., family Mixodectidae, one of the so-called " Proglircs." xi. 



radiate from trituberculy into quadrituberculy, and into crested forms. 

 Osborn's recent revision 1 of the American Eocene Primates proves 

 that the molars exhibit a fundamentally triangular pattern in every 

 one of the twenty-two or more known species. The various types 

 exhibit a familiar succession of stages from a more triangular condition 



r? <_/ 



with an extremely rudimentary hypocone, to a quadrate, sexitubercular 



1 null. Amtr. Mus. Nat. Hint., Vol. XVI., 1902, pp. 169-214. 



