J. B. Hatcher — Recent and Fossil Tapirs. 179 



doubtless have one of the direct ancestors of the modern Tapir. 

 In this species sup. pm. 4 is entirely molariform except that 

 the posterior cross-crest is not complete. Sup. pm. 3 is in the 

 same stage as sup. pm. 2 in T roulini of recent Tapirs. 

 Tapirus helveticus Meyer is perhaps the European equivalent 

 of Tapiravus validus Marsh, from New Jersey. The Euro- 

 pean species should be referred to the latter genus rather than 

 to Tapirus. In regard to the American species at present 

 referred to Protapirus, there may be considerable doubt as to 

 whether they should not be referred to a distinct genus ; from 

 Filhol's description and figures there would seem to be a con- 

 siderable difference in the relations of the protoloph to the 

 parastyle in the sup. true molars and in the structure of the 

 posterior cross-crest in sup. pm. 4. The importance of these 

 differences can only be determined by an actual comparison of 

 the specimens. 



Of recent Tapirs it can be pretty well demonstrated that 

 Elasmognathus bairdii, the most specialized of all, has been 

 derived from T. roulini directly through T. terrestris and E. 

 duwi ; while T indicus had a common ancestry and became 

 separated from the others, probably in late Miocene times, 

 since when it has paralleled Elasmognathus in some of its 

 characters though not showing the same degree of specializa- 

 tion. 



In regard to Colodon and the earlier genera of pseudo-tapirs, 

 I cannot agree with Osborn and Wortman that their line of 

 descent has been entirely distinct from that of the true Tapirs. 

 On account of the, in many respects, very similar tooth and 

 foot structure of the two, it would seem that they were both 

 derived from a common Bridger ancestor, most likely some 

 one of the species now referred to Helaletes and which had its 

 immediate ancestor in Systemodon. The true genus Helaletes 

 with sup. pms. 3 and 4, already molariform according to W. 

 and E., terminates a third line, and is descended directly from 

 Heptodon of the Wind River. 



The figures in the plates accompanying this paper were 

 drawn by Mr. Rudolph Weber. I wish here to express my 

 thanks to Prof. Scott for his kindness in allowing me to 

 describe the important and rare skull of Protapirus as well as 

 the other fossil material. To Prof. Marsh I am especially 

 indebted for the free use of the very complete collection of 

 skulls and skeletons of recent Tapirs in the Yale Museum. I 

 wish also to thank Mr. F. A. Lucas of the National Museum 

 and Prof. Osborn and Dr. Wortman of the Am. Mus. of Nat. 

 Hist, for the use of material in their charge. 



Princeton, N. J., Jan. 13, 1896. 



