TO THE 



:2lcaiiemi) of J^'atural Bdtnas 



OF PHILADELPHIA; 



TO WHOSE FOUNDERS IS DUE THE FIKST EFFECTIVE IMPULSE GIVEN 



TO THE STUDY OF THE NATURAL SCIENCES IN NORTH AMERICA, 



AND WHOSE LABORS HAVE BEEN MAINLY INSTRUMENTAL IN 



DEVELOPING THE NATURAL HISTORY OF THE COUNTRY, 



THIS WORK IS RESPECTFULLY INSCRIBED BY 



THE AUTHOR. 



