CHAP. Vl] THE DENTAL SYSTEM OF THE PRIMATES 297 



of the Honiinidae. The character has not been lately acquired, for the giant 

 extinct Lemurs possess it (cf. Chapter xvn.), and it is worthy of remark 

 that the same incisor form is found in the early Triassic Reptilia. But 

 Cope (Am. Nat. 1893) was able to shew that several of the extinct Adapidae 

 possessed a more generalized conformation in regard to the teeth in question. 

 The typical Lemurine conformation is regarded as the result of adaptive 

 specialization, and is not shewn by the Middle Eocene form of Lemur 

 designated Notharctus (Gregory 1913). The condition of the lower incisors 

 in the Lower Eocene form Anaptomorphus is obscure. 



From the small Eocene American Lemuroids, Cope considered 

 that a transition is easily demonstrable to extinct Eutherian 

 groups known respectively as the Condylarthra (a parent ungulate 

 stock) 1 , or even to the Creodonta (ancestral carnivorous forms). 

 The possibility of re-tracing the evolution of the Primates to the 

 Creodonta is of great importance. For Cope held that the Creo- 

 donta were in turn derived from ancestors of a very primitive 

 Marsupial or Metatherian (polyprotodont) type. Forsyth-Major 

 (Proc. Zool. Soc, 1893) and Marett Tims strenuously oppose this 

 view, while Professor Gregory in 1913 2 recognizes the close affinities 

 of the early Creodonts with the early Insectivora. In Gregory's 

 opinion their distinction and separation must have occurred long 

 before the beginning of the Tertiary period. In view of the 

 recent extension of knowledge in regard to the anatomy and 

 dentition of the Insectivora, it is now unnecessary to introduce the 

 Creodonta into the ancestral line of the Primates, and reference 

 to the scheme published by Dr Gregory (cf. Fig. 11 sitjjra) 

 shews the relative positions to be assigned on modern evidence to 

 the Primates, Insectivora and Creodonta respectively 3 . The dental 

 evidence is weighty on the side of confirming that scheme and the 



1 Cf. Osborn, 1907, p. 168. 



-' Bulletins of the American Museum of Natural History, Vol. xxvn. p. 307. 

 3 The sequence for the Primates given by Schlosser in 1911 is as follows (cf. 

 Gregory, Bulletins of the Geological Society of America, Vol. xxiii. June 1912). 



Honiinidae (recent). 



Simiidae (recent). 



Pliopithecus (Pliocene). 



Propliopithecus (Upper Eocene or Oligocene). 



Paiapithecus (Upper Eocene or Oligocene). 



Tarsiidae (recent). 



Anaptomorphidae (Lower Eocene). 



