PHYSIOLOGY OF SYNAPTULA HYDRIFORMIS 



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gives none. If the concentration of the salts in sea-water is 

 taken as 5/8 M, (Mayer, '11, '14), then the former dilution cor- 

 responds to 1/2 M, i.e., a change of 1/8 M is sufficient to cause 

 a reaction. On the other hand, 6 cc. sea-water + 4 cc. sea-water 



TABLE 7 

 Limiting concentrations of chemical agents 



TABLE 8 



Minimum concentrations of chemical agents which will rail forth responses when 

 applied to the mouth of certain vertebrates or the tentacles or mouth region of 

 certain invertebrates 



N.R. signifies that there was. no reaction. 



