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



There are marked differences in the structure of the sup. true 

 molars in the two species and when the complete dentition of 

 the Uinta species is known, the dental formula and arrange- 

 ment of the teeth will doubtless be found to differ in the two. 

 If Isectolophus {Helaletes) latidens can be shown to differ 

 generically from Helaletes it should be made the type of a new 

 genus. I have never seen any of Prof. Marsh's types of Hela- 

 letes and his descriptions do not permit of an identification of 

 other material. 



The discovery of a nearly complete skull of Protapirus with 

 characteristic tapirine characters, already pointed out, may be 

 considered as additional evidence in favor of Wortman and 

 Earle's views in considering that genus as the White River 

 ancestor of the Tapirs. In taking this view of the question, 

 however, the fact must not be lost sight of, that in Protajpirus 

 the character of the metacone of the sup. molars is not what 

 we should expect to find in a White River Tapir, and the 

 inferior, external, lateral incisor is much smaller than we 

 should expect it to be, since it persists in recent Tapirs and is 

 even proportionately larger than in Protapirus. The metacone 

 in Protapirus is placed father in, and is less prominent and 

 not so convex externally as in Isectolophus, while the same ele- 

 ment in recent Tapirs is more prominent and has a more exter- 

 nal position than in Isectolophus. Thus, according to our 

 present phylogenetic arrangement we should have to allow for 

 first a gradual shifting inward of the position of this cone fol- 

 lowed by a period when it commenced to move outward to its 

 normal position in modern Tapirs / a rather extreme case of 

 oscillation but not entirely inconsistent with what Scott has 

 shown to have taken place in the Equine series. 



Very little is known of the American Miocene representa- 

 tives of the Tapir line. Prof. Marsh has mentioned the occur- 

 rence of two Miocene species of Tapiroids which he considers 

 as standing ancestral to the Tapirs. One of these is from the 

 Miocene of New Jersey and the other is from the Loup Fork 

 or late Miocene (early Pliocene of Marsh) from east of the 

 Rocky Mountains, no more definite locality being given by 

 Marsh. These specimens are made the type of a new genus 

 Taptravus / the one from New Jersey is described as Tapiravus 

 validus, while the one from the west is called T. rarus. I have 

 never seen either of these specimens and they have not been 

 figured, and are only very briefly described by Prof. Marsh. 

 There would seem to be little doubt that they belong to the 

 direct line leading to the recent Tapirs. 



In Europe the paucity of Tapir remains in the Miocene is 

 almost as marked as in America. In Tapirus helveticus of 

 Meyer, from the lower Miocene of Eselsberg near Ulm, we 



