100 WILLIAM A. KEPNEE AND ARNOLD RICH 



food ingestion, but this only when the entire musculature of the 

 proboscis is intact. The freed proboscis had not the ability to 

 distinguish between food and non-food. The exercise of choice 

 is made possible only through the functioning of the central 

 nervous system. 



LITERATURE CITED 



Darwin, Charles 1843 Journal of researches during the voyage round the 



world in H. M. S. Beagle, 2nd ed. New York. 

 Gamble, F. W. 1901 The Cambridge natural history, vol. 2, London. 

 Leidy, Joseph 1847 Description and anatomy of a new and curious subgenus 



of planaria. Proc. Acad. Nat. Sci. Philadelphia, vol. III. 

 Monti, R. 1897 Sur le systeme nerveux des Dendrocoeles'd'eau douce. Arch. 



Italien. de Biol. T. 27. 

 Pearl, Raymond 1903 Movements and reactions of fresh-water planarians: 



a study in animal behaviour. Quart. Journal Micr. Science, vol. 16. 

 Steiner, J. 1898 Die Functionen des Centralnervensystems und ihre Phylo- 



genese: Dritte Abth. Die wirblellosen Thiere. Braunschweig. 

 Walter, Herbert E. 1908 The reactions of planarians to light. Jour. Exp. 



Zool , vol. 5. 



