lU 



Annals of the Carnegie Museum. 



Horizon. 



Protoceras Beds. 



Oreodoii Beds. 



[Uppe 



I 

 Titanothe- | 



Ser es I. Series II. 



I. TT oval in cross-section and I.^ triangular in crosssec- 



procumbent. Manus usually tion and obliquely fixed in jaw. 



tetradactyl. Manus tridactyl so far as at 



Ancestral to the Miocene present known. 

 Aceratheres and the true Ancestral to the Dicera- 



Rhinoceroses. theres. 



Aceratherium platycepha- 

 lum. 



Representatives of this series 

 undoubtedly present, but as yet 

 undiscovered. 



Leptaceratherium trigono- 

 dum. 



Leptaceratherium trigono- 



rium Beds. ] Middle, dum. 



I Aceratherium mite. 



I Lozver. Trigonias osborni. 



Diceratherium (.-Vcerather- 

 ium) tridactylum. 



Aceratherium occidentale. 

 Aceratherium copei. 



Representatives of this series 

 as yet undiscovered in Titano- 

 therium Beds. 



Explanation of Plates. 

 Plate I. 



Fig. I. Crown view of left ramus (No. 97) of Trigonias osfiorni, ^{ natural size. 



Fig. 2. Side view of left ramus (No. 97) of Trigonias osborni, ],{. natural size. 



Fig. 3. Crown view of superior teeth (No. lOO) of type of Leptochceriis qitadri- 

 cuspis, twice natural size. 



Fig. 4 Crown view of superior teeth of L. gracilis, twice natural size. After 

 Marsh. 



Figs. 5 and 6. Crown view of dental plate (No. 104) of Platacodon nanus, three 

 times natural size. 



Fig. 7. Crown view of superior molar (No. 99) of Orohippus ? sp. Natural size. 



Fig. 8. View of dermal impression of Claosatiriis annecte)is, preserved on block 

 of sandstone (No. 105). Natural size. 



Plate II. 



Fig. I. Side view of skull (No. 96) of Trigonias osborni, }{ natural size. 



Fig. 2. Crown view of superior dentition (No. 9S) of T. osborni, yi natural size. 



Plate III. 



Fig. I. Oblique front view of right manus of Trigonias osborni: s, scaphoid; 

 /, lunar;//, pyramidal ; id, trapezoid ; ;//, magnum; n, unciform. A little less than 

 half natural size. From a photograph. 



Fig. 2. Inner side of right manus of Trigonias osborni : pi, pisiform ; .r, scaphoid ; 



/, lunar; //«, trapezium; A/, trapezoid; »i, magnum. About one half natural size. 



From a photograph. 



Plate IV. 



Fig. I. External side view of right scapula, limb and manus of T osborni in 

 position. About I natural size. (From a photograph. ) 



