I 76 Bulletin American Museum of Natural History. [Vol. XVI, 

 II. LOWER, MIDDLE, AND UPPER EOCENE PRIMATES. 



(SPARNACIEN, YPRESIEN, LUTETIEN, BARTONIEN, LIGURIEN.) 



Originating in the lower Eocene or Wasatch (Sparnacien, 

 Ypr^sien) of North America are found three phyla of Pri- 

 mates, quite distinct from those in Europe. 



1. The Hyopsodontid^ are analogous in certain respects 

 of molar tooth structure to the Microchceridae of Europe, but 

 are distinct in the simple cutting teeth. 



2. The NoTHARCTiD^ resemble in size and general form 

 the contemporaneous Adapidae of Europe, but the much more 

 complex structure of the upper molars constitutes good 

 grounds for not placing them in the same family. 



3. The very specialized Anaptomorphid^ so far as known 

 (skull, teeth and jaws only) remotely resemble the living 



Fig. 3. Superior molars. A ^ Adapis magnus : B, Hyofisodus uin- 

 tensis, type ; C, Notharctus sp. 



Tarsiidae of the Oriental region, but it seems to be a pre- 

 mature conclusion to place them in the same family because 

 they are so widely separated geologically and geographically. 



The European Eocene Primates, also placed in three 

 families, Adapidae, Microchoeridae, and Plesiadapidae, are now 

 generally (Trouessart, '97) referred to the Lemuroidea. The 

 force of Schlosser's remark ('87, p. 19) uniting them in the 

 distinct suborder Pseudolemuroidea ("This suborder includes 

 only extinct forms, which certainly mark a transition between 

 the true Monkeys and Lemurs, but stand in direct genetic 

 relations neither with one nor the other") has been vigorously, 

 disputed by Leche ( '96), who, on the ground of resemblances 

 in milk succession, places certain of these families (Micro- 

 choeridae) in the Lemuroidea. 



It may be possible with the material now in hand to 



