f QLS84- 



BIOLOGY 



LIBRARY 



G 



COMMISSION 



TO WHICH THIS MEMOIR HAS BEEN REFERRED. 



C. ZlMMKRMANN, 



F. E. MELSUEIMER. 



JOSEPH HENRY, 



Secretary S. I. 



COLLINS, I&quot; K I N T K 1! , 

 PHILADELPHIA. 



