BEHAVIOR OF METRIDIUM. 43 



is directed with a pipette against the expanded disk, the animal 

 contracts strongly. Waiting till it has again expanded, the 

 stream of water is directed upon it as before. This time it does 

 not react. In specimens that are not in good condition, this 

 change of behavior cannot be seen. The animal does not con- 

 tract at all save under strong stimuli, and if such are repeated, it 

 contracts as at first. 



PAPERS CITED. 

 Jennings, H. S. 



'05 Modiriability in Behavior. I. Behavior of Sea Anemones. Journ. Exper. 

 Zool., II., No. 4. 



Nagel, W. A. 



'92 Das Geschmacksinn der Actinien. Zool. Anz., XV., 334-338. 

 Parker, G. H. 



'96 The Reactions of Metridium to Food and Other Substances. Bui. Mus. 

 Comp. Zool. Harvard College, XXIX., 102-119. 



'05 The Reversal of Ciliary Movements in Metazoans. Amer. Journ. Physiol., 

 XIII., 1-16. 



The Reversal of the Effective Stroke of the Labial Cilia of Sea Anemones by 

 Organic Substances. Amer. Journ. Physiol., XIV., 1-5. 



