412 Wartman — Studies of Eocene Mammalia in the 



Hallux and pollex fully opposable ; three true molars ; lachry- 

 mal reduced ; lachrymal canal opening on or inside orbital rim; 

 premolars progressively reduced to two in advanced forms ; 

 brain enlargement progressively increasing in the later types ; 

 five families. Neopithecini. 



The Neopithecini are divisible into at least iive distinct 

 families of which in the living fauna three are confined to the 

 Old World* and one to the New World. One extinct family 

 is common to the two hemispheres, and as far as can be now 

 ascertained from the remains, occupies a position not far 

 removed from the common primitive stem from which the 

 great majority of the living simian population of the Old and 

 New Worlds originated. In the case of the Old World 

 families, the gap is as yet very wide, but in the cas'e of the 

 New World Cebidse, the interval is much less, and is not 

 greater than one would be reasonably led to anticipate between 

 an ancestor of Upper Eocene time and a living descendant. In 

 fact, the difference is not nearly as great as it is between the 

 modern horse arid its Upper Eocene progenitor, Orohippus. 

 As this phase of the subject will be more fnlly discussed in 

 another section of the present paper, it may be here dismissed. 



The families of the Neopithecini are distinguished upon 

 osteological considerations, as follows : 



Premolars four above and below ; orbital and temporal fossae 

 more or less freely continuous ; parietal uniting with alisphenoid 

 on side wall of cranium ; molars more or less fully quadrituber- 

 cular, with ridges of superior trigon distinct; a large petrotym- 

 panic bulla expanded behind ; external auditory meatus not 

 prolonged into a tube ; carotid canal piercing bulla near postero- 

 external angle ; a postglenoid foramen ; muzzle elongate ; 

 lachrymal slightly extended beyond rim of orbit, with opening of 

 lachrymal canal upon edge of orbit ; ilium little expanded ; 

 ischium without distal enlargement or everted edges ; head of 

 femur more or less sessile upon shaft ; digital fossa of femur 

 narrow and slitlike ; a third trochanter and an entepicondylar 

 foramen ; hallux fully opposable ; metatarsal of hallux with 

 elongate proximal plantar extremity ; pollex not as fully oppos- 

 able as in higher species ; foramina of atlas complex. Adapidae. 



Premolars three above and below ; orbital and temporal fossae 

 separated by bony plate ; parietal uniting with alisphenoid on 

 side wall of cranium ; frontal excluded from contact with alisphe- 

 noid by malar on side of skull (except in Mycetes and some 

 species of Ateles) ; molars fully quadritubercular, with ridges of 

 superior trigon distinct; first lower premolar without elongate 



* In this statement, the origin of man is considered to have taken place in 

 the Old World. 



