Io8 Bulletin American Museum of Natural History. [Vol. XVI, 



several specimens in the American, Harvard, and National 

 Museums. 



B. ramosum Osborn. — There is some question whether this 

 is really distinguishable from B. cnrtmn. 



Fig. 13. Comparative fronto-nasal sections and horn contours. Showing progressive shift- 

 ing forward of horns, and abbreviation of free portion of nasals. Brontotherium leidyi, Lower 

 Beds. Brontotherium hypoceraSy Middle Beds. (Nat. Mus. No. 4702.) Brotitotherittin 

 hypoceras. (Nat. Mus. No. 4273.) The dotted vertical line shows the position of the orbit. 



B. platyceras Scoit & Osborn. — Type in the Harvard 

 Museum. 



BIBLIOGRAPHY. 



1887. — Scott, W. B., and H. F. Osborn.^ Pi-eliminary Account of 

 the Fossil Mammals from the White River Fonnation con- 

 tained in the Museum of Comparative Zoology. [Titano- 

 there Contributions No. i.] BzM. Mus. Com p. Zodl., Vol. 

 XIII, No. 5, pp. 151-171, pll. I-II, Aug., 1887. 



1893. — Hatcher, J. B. The Titanotherium Beds. Ainer. A^at., 

 March i, 1893, pp. 204-221. 



1895. — Osborn, Henry F. Perissodactyls of the Lower Miocene 

 White River Beds. [Titanothere Contributions No. 2.] Bull. 

 Amer. Mus. Nat. Hist., Vol. VII, Art. XII, pp. 343-375, 

 pll. VIII, IX, Dec. 23, 1895. 



