BEHAVIOR OF LOWER INVERTEBRATES 387 



the fact that the intensity of the light is increased. Artemia 

 reacts in much the same way as Daphnia, and the author con- 

 cludes that lights of different wave lengths produce different 

 effects. 



Frolich (21) has experimented on the isolated eyes of Octopus, 

 noting fluctuations in the current of action under constant stim- 

 ulation by light. Rhythmical fluctuations of the current were 

 noted which varied in frequency and extent with the intensity 

 and wave length of light. 



Gee (22) has made a thorough investigation of the behavior 

 of two species of leeches, Dina microstoma Moore and Glossi- 

 phonia stagnalis L. His paper includes a description of the 

 general habits of the two species; their various movements; 

 food and feeding; reactions to light, heat, currents of water, 

 and chemicals; daily changes of behavior; the behavior of the 

 young, and various other features of the normal activities of 

 these animals, thus affording a foundation for the analytical 

 work which follows. Under the head of modifiability of beha- 

 vior are treated the various responses of the animal to repeti- 

 tions of the same stimulus and their different determining fac- 

 tors, acclimatization to stimuli, fatigue, depression induced by 

 various chemicals and its relation to fatigue, and the influence 

 of hunger and satiety on various reactions. Of particular interest 

 is the parallelism between the effects of fatigue and influence 

 of those substances, sarco-lactic acid, carbon dioxide, etc., which 

 are supposed to cause fatigue in higher forms. 



Gee's paper (23) on the modifiability of behavior in the sea 

 anemone Cribrina embodies an attempt to account for the 

 changes of behavior in this form in terms of certain physiolo- 

 gical processes. Food produces a copious secretion of mucus 

 and after a certain amount of food has been taken in the animal 

 refuses to take more. Why does the surfeited anemone reject 

 the food ? It is not due to fatigue of the muscles involved in 

 prehension or swallowing. If the anemones are stimulated by 

 beef extract or oyster juice they secrete mucus copiously and 

 soon reject solid food. Various salts were found to cause the 

 anemone to reject food. The refusal of food is not the result 

 of conditions of assimilation; apparently it is the effect of con- 

 ditions brought about by the secretion of mucus. Cribrina 



