RESEARCHES 
UPON 
NEMERTE ANS and PLANARIANS. 
BY 
CHARLES GIRARD, 
CORRESPONDING MEMBER OF THE ACADEMY OF NATURAL SCIENCES, PHILADELPHIA, 
THE BOSTON SOCIETY OF NATURAL HISTORY, m*rrn THE LYCEUM OF NATURAL 
HISTORY OF NEW YORK, j MEMBER OF THE AMERICAN ASSOCIATION 
FOR THE ADVANCEMENT OF SCIENCE, AND THE 
NATIONAL INSTITUTE OF WASHINGTON. 
I. 
EMBRYONIC DEVELOPMENT OF PLANOCERA ELLIPTIC A, 
PHILADELPHIA: 
MERRIHEW AND THOMPSON, PRINTERS, MERCHANT STREET, ABOVE FOURTH. 
January, 1854. 
