EXPERIMENTS ON ACTINIANS 



49 



The unreliability of this interpretation is apparent, 

 however, from the fact that Claus considers it uncer- 

 tain. He mentions the possibility of a conduction of 

 stimuli as one of the conditions that speak for the ex- 

 istence of a nervous system in Actinians. But a COD- 



FIG. 10. THE ABILITY OF THE ACTINIANS TO DISCRIMINATE. 



The tentacles press the meat a into the mouth, while they drop the water-soaked 



paper b. 



duction of stimuli also occurs in plants. During the 

 year 1888 in Kiel, and 1889-90 in Naples, I made in- 

 vestigations on the reactions of Actinians, which show 

 how little reason we have for concluding that compli- 

 cated reactions need depend upon similarly compli- 

 cated reflex centres (i). It is very obvious from these 

 experiments that the structure and irritability of the 

 peripheral organs determine the reactions. We will 

 begin with the description of experiments on the Ac- 

 tinia cquina (mesembryanthemuvi) of the East Sea. 



