208 



W. C. ALLEE AND SHIRO TASHIRO 



TABLE 2 



Showing the effect of calcium chloride upon carbon dioxide production and rheo- 

 taxis in isopods. The survival time in potassium cyanide is added for comparative 

 purposes. The isopods were first tested for rheotaxis, then two of approximately 

 the same size were taken for determination of their carbon dioxide output in the 

 biometer. The one of these that gave the least carbon dioxide was taken as a con- 

 trol, its rheotactic reaction was again tested and it was allowed to stand in water 

 to which it was accustomed while the other was treated. 



The second isopod, the one giving the most carbon dioxide, was placed in a 0.16 

 mol. solution of calcium chloride until the positive rheotactic tendency was mark- 

 edly decreased. Immediately afterward the carbon dioxide production of the two 

 was again compared in the biometer. 



