Department of Vertebrate Palceontology. 



the Middle Eocene Period (Bridger and Washakie). The foot 



bones are not cast separately. 



The especial interest of the Titanothere fore foot is that it 



is essentially paraxonic (Artiodactyl) although belonging to a 



member of the Perissodactyla, with a typically Perissodactyl 



(mesaxonic) pes. Several other Artiodactyl characters are 



found in this family, supporting Cope's contention that the 



Perissodactyla and Artiodactyla should be united in a single 



order (Diplarthra). 



Price, Ss- 



Nos. 4 and 5. Diplacodon emarginatus Hatcher. 

 Front of Skull and Lower Jaw. 



Cast, by courtesy of the Princeton University Museum, 

 from the type specimen described by Hatcher. 



It shows the intermediate stage in the development of 

 the horns between the ancestral Titanotheres of the Middle 

 Eocene, hornless or with very rudimentary horns (PalcBosyops 

 and Tehnatotherium), and the horned species (Titanotherium) of 

 the Oligocene. The greatest diameter of the horns is antero- 

 posterior, and both the nasals and frontals enter to some 

 degree into the base. Diplacodon is found in the Upper or 



True Uinta Beds of the Upper Eocene. 



Price, $15. 



Hatcher, On a New Species of Diplacodon, Am. Nat., 1895, p. 1084, 

 pi. xxxviii. 



No. 6. Dromatherium sylvestre Emmons. 

 Type Lower Jaw. 



Cast, by courtesy of the Geological Museum of Williams 

 College, from the original. 



This classic specimen is the better preserved of the two jaws 

 found by Prof. Ebenezer Emmons in 1854 in the Triassic Coal 

 Beds of Egypt, North Carolina. It is distinguished from the 

 jaw of a reptile by apparently consisting of a single bone, while 

 the teeth begin to show two fangs and multiple cusps prophetic 



of the mammal type, the Protodonta of Osborn. 



Price, $j. 

 Emmons, American Geology, Part VI, p. 93. 

 Osborn, Proc. Acad. Nat. Sci. Phila., 1886, p. 359. 



