No. 536] ADAPTATIONS OF THE PRIMATES 485 



during that time they shortened the skull and lost the 

 first two premolars, and made a considerable increase in 

 size. In Europe their remains are very scarce and con- 

 fined to the Lower Oligocene when it was the true Adapts 

 which was holding over from the Eocene. Schlosser has 

 just reported some primates from the Fayum formations 

 of Oligocene age in northern Africa. These he gives new 

 generic names, Mceripithecus, Parapithecus and Proplio- 

 pithecus, assigning the first two to the Cercopithecidas 

 and the last to the Siiniidse. They seem from the de- 

 scriptions to be primitive members of the Cercopithecidas, 

 which would indicate that the change to the modern type 

 by the loss of the first two premolars was accomplished 

 in the early Oligocene, perhaps in Africa as the two areas 

 are in connection at the time across Gibraltar. 7 



At the beginning of the Miocene the European primates 

 had the dental formula 2 / 2 , K, %, %=32, a shortened face, 

 and a shortened tail, but were still arboreal forms. Dur- 

 ing the Lower Miocene two divisions arise, the one adher- 

 ing to the quadrupedal gait, the heavy jaws and longer 

 snout : the other acquiring the bipedal gait, and shorten- 

 ing the face with a corresponding broadening of the 

 teeth. In both divisions there is a tendency to come 

 down to the ground. 



The former group is the Cercopithecidas in its broad 

 sense, or "old world monkeys"; while the latter are the 

 Simiidas or apes. 



The Cercopithecidas seem to run back to some such form 

 as the Oreopithecus, found in northern Italy, and present- 

 ing dental characteristics resembling the baboon, but at 

 the same time having a shortened face suggesting the 

 Simiida?. A second form belonging to this group is 

 Mesopithecus found in considerable abundance in the 

 Lower Pliocene of Greece. This form seems to be in- 

 termediate between the macaques and langurs, resem- 



7 For geography see Matthew, Bull. Amer. Museum Nat. Hist., Vol. 22, 

 p. 364, 1906. For the Fayum Primates, see Zoologiscten Anzeiger, Bd. 35, 

 for March, 1910, and Matthew, Amer. Nat., Vol. 44, Nov., 1910, p. 700. 



