ART. 1. PRIMATES OF THE FORT UNION GIDLEY. 33 



Gregory, the annulus in Noiharctus, while free, is not so completely 

 covered by the bulla as in the Madagascar lemurs. Thus it would 

 seem that while structurally nearer this group the Notharctid stage 

 of development, after all, takes an intermediate place tending toward 

 the condition observed in the Platyrrhini and away from the true 

 lemur type. 



The development of the otic bulla in connection with its relation 

 to the tympanic ring will be more fully discussed in another article 

 now in preparation. 



SUMMARY AND CONCLUSIONS. 



As a result of the foregoing studies, several important conclusions 

 are suggested, which, though for the most part still lacking positive 

 demonstration, seem at least worthy of serious consideration. For it 

 is only by such methods of comparison and discussion that one may 

 hope ever to attain, or even approximate, the ultimate truth regard- 

 ing the evolutionary history of animal Hfe of the past as recorded by 

 fossil remains. Especially is this evident when it is considered how 

 very incomplete at best is the story of development in attempting to 

 trace those ancient phyletic series which are based, as they necessarily 

 must be, on the present relatively scanty and broken records. For 

 at best, in our fossil records there exist many wide gaps, which in 

 many cases probably will never actually be filled, although future 

 discoveries in the fossil fields may greatly aid in this matter. 



Some of the following conclusions have been advocated and de- 

 fended in part or in whole by other authors, but in greater part they 

 have been suggested by my own lines of investigation. These con- 

 clusions may be thus briefly summarized: 



1. The evidence of the Fort Union mammals, as at present known, 

 seems to show conclusively that the major groups at least of the 

 Tarsiidae, as defined by Matthew, had their origin much earlier than 

 the beginning of the Eocene, being almost as well marked in the 

 Paleocene as in the Wasatch and Bridger. 



2. The early Tarsiids, as at present understood, seem not to repre- 

 sent a natural group. That is, certain forms, now referred to this 

 group on definition of tooth characters alone, when better known, 

 may lose their present taxonomic arrangement of closely affiliated 

 species. 



3. It would seem, however, that within this group are to be found 

 the ancestral stock which gave rise to the living Tarsiers, they being 

 derivable from some such forms as Omomys or AnaptomorpJius; and 

 possibly the origin of the aberrant lemur, Daubentonia of Madagascar 

 also may be traced to some other form of this group with the dental 

 modifications of Phenacolemur, or Tetonius. 



5596— 24— Proc.N.M. vol.63 3 



