EOCENE AND OLIGOCENE TITANOTHERES OF MONGOLIA 



917 



of the upper part of the Bridger formation of Wyoming and 

 Utah. 



Manieoceras (generic reference doubtful) of the Irdin Manha 

 formation; the "prophet-horned" titanothere, somewhat similar 

 to the Manteoceras of the upper part of the Bridger formation 

 of Wj^oming and the Uinta Basin of Utah. 



Metarhinus (generic reference doubtful) of the Irdin Manha 

 formation; somewhat similar in its diminutive size to the 

 Metarhinus fluviatilis of northern Utah and southern Wyoming. 



The distinctive characters of four well-established 

 American genera — DolicTiorTiinus, Telmatherium, Pro- 

 titanotJierium, and Brontops — may be contrasted with 

 those shown in the following table, which is based 

 upon the chief characters of the Asiatic forms : 



E G 



Figure 774. — Comparative views of jaws of upper Eocene titanotheres from 

 the Irdin Manha and Shara Murun formations of Mongolia 



A, Protitanotherium andreii'si, large male jaw (Am. Mus. 20272), Shara Murun formation (compare 

 fig. 786); B, Prolitanotherium grangeri, large male jaw (Am. Mus. 20105), Irdin Manha formation; 

 C. PTOiUanotherium grangeri, large male jaw (Am. Mus. 20101), Irdin Manha formation; D, Telma- 

 therium berkeyi, type female jaw (Am. INIus. 20106), Irdin Manha formation; E, BolichoThinus 

 oheni, type male jaw (Am. Mus. 20109j, Irdin Manha formation; F, Ifanteoceras? irdijiensis. type 

 jaw (Am. Mus. 20111), Irdin Manha formation; G, Metarhinusf mongoUensis, type jaw (Am. 

 Mus. 20167), Irdin Manha formation. .AH one-eighth natural size. 



FiGUEE 775. — Comparative occipital views of the chief 

 titanotheres of MongoUa in descending geologic order 



A, Brontops gobiensia, occiput of type cranium (Am. Mus. 20354), Ardyn 

 Oho formation; B, Protitanotherium andrewsi, occiput of type cranium 

 (Am. Mus. 20271), Shara Murun formation; C, Protitanotherium gran- 

 geri, occiput of type cranitma (Am. Mus. 20103), Irdin Manha forma- 

 tion; D, OoUchorhinus haiseni, occiput of type cranium (Am. Mus. 

 20252), Shara Murun formation. All one-sixth natural size. 



