THE 



, OR PIGS. 



143 



to the present living Peccary, and, with the exception 

 of a few species, is one different from that of the 

 primordial world. In this series we find repeated 

 the transformations and reductions which we have 

 just followed. Marsh makes out the line from 

 the Eocene thus : Eohyus, Helohyus, Perchcerus, 

 Tinohyus, Dicotyles. Hence we still stand before 

 the unanswered questions, whether, to what extent, 



FIG. 17. Pala?ochcerus typus, Left Upper Jaw. Nat. size. 



After Gaudry. 



and in which direction (from Europe westwards? 

 from Asia ? or from America ?) the exchange took 

 place, as affecting the formation of the differences 

 of the species ? or whether the development was a 

 parallel one ; Choeropotamus to the Pig, Eohyus to the 

 Peccary? Geologists are pretty well agreed that 

 during the Earlier Tertiary period, up to the Lower 

 Miocene, the Old and New World were connected by 



