SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE. 



MEMOIR 



MOSASAUEUS 



THREE ALLIED NEW GENERA, 



HOLCODUS, CONOSAURUS, AND AMPH O R O S T E US. 



By ROBERT W. GIBBES, M. D. 



CORRESPONDENT OF THE ACADEMY OF NATURAL SCIENCES, PHILADELPHIA, OF THE BOSTON SOCIETY OF 

 NATURAL HISTORY, ETC. 



[Read before the American Association for the Advancement of Science, August, IS49.] 

 [Received, November 15, 1849,] 



