31 2>n 



Behavior Monographs 



Volume I, Number 4, 191 1 Serial Number 4 



Edited by JOHN B. WATSON 



The Johns Hopkins University 



The Biology of Physa 



JEAN DAWSON 



Published 



at Cambridge, Boston, Mass. 



HENRY HOLT & COMPANY 



34 West 33d Street, New York 



G. E. STECHERT & CO., London, P«ris and Leipzig. Foreign Agents 



