I 78 Bulletin American Museum of Natural History. [Vol. XVI, 



The extensive material in the American Museum is at the 

 disposal of any thoroughly competent investigator who desires 

 to exhaustively study this group. The present revision, 

 while not final, will certainly be of service. 



GEOLOGICAL DISTRIBUTION. 



Order MESODONTA Cope. 



Pachylemuriens FiUiol, in part; P seudolemuroidea Schlosser, in part; 

 Tarsii Gill, in part. 



Characters: Primitive Primates. Incisors typical or reduced to f ; 

 canines typical or enlarged, premolars I to I; molars |; upper molars 

 ranging from trituberculy to sexituberculy ; lower molars ranging from 

 quinquetuberculy (tuberculo-sectorial) to quadrituberculy. Lachrymal 



