176 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



Etymology. — uintensis, from Uinta, in allusion to the 

 Uinta Basin. 



Present determination. — This is a valid genus and 

 species. (See p. 419.) 



Protitanotherium Hatcher, 1895 



Cf. Protitanoiheriiim Hatcher, this monograj)h, page 374 

 Original reference. — Am. Naturalist, vol. 29, p. 1084, 

 December, 1895 (Hatcher, 1895.1). 



would seem that Professor Marsh's conclusion is entirely con- 

 jectural, since his material does not show whether there were 

 horns or not. The present skull has a well-developed pair of 

 frontonasal horns, and, since it agrees in all the characters 

 known to that genus, I have preferred to refer it to that genus 

 rather than to propose for it a new one on the strength of this 

 purely conjectural character ascribed to Diplacodon by Pro- 

 fessor Marsh. Should future discoveries show that there are 

 hornless forms with the same dental characters as Diplacodon, 

 it will then be necessary to establish for the present specimen a 

 new genus, which may be called Protitanotherium. 



FiGUKE 112. — Type (holotype) of Diplacodon emarginatus 



Facial part of skull and anterior part of mandible. Princeton Mus. 11242. After Hatcher, 1895. Ai, Az, Aj, Side, top, and front views of 

 skull; Bi, B2, B3, side, top, and front views of mandible. One-fourth natural si:e. 



Type species. — Diplacodon emarginatus Hatcher. 

 Generic characters. — Hatcher writes: 



In referring this skull to Diplacodon, I have been compelled 

 to ignore certain characters ascribed to that genus by Professor 

 Marsh. That author, in speaking of the relations of this genus 

 to the Titanotheriidae (Brontotheridae) , in his original descrip- 

 tion of the type specimen, says (Marsh, 1875.1, p. 24) : "From 

 this family, Diplacodon differs widely in its dentition and the 

 absence of horns." In describing Diplacodon as hornless, it 



Etymology. — pro, before; Titanotherium — that is, 

 forerunner of Titanotherium. 



Present determination. — It is not yet settled whether 

 Diplacodon elatus Marsh had horns or not, but it is 

 now believed that even if this character is set aside 

 D. elatus is generically distinct from D. emarginatus, 

 and we may therefore regard Hatcher's Protitanothe- 

 rium as a valid genus. 



