TABLE 6 



Showing the effect of calcium chloride upon carbon dioxide production and rheotaxis in 

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

 poses. 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 bi- 

 ometer. The one of these that gave the least carbon dioxide was taken as a control, 

 its rheotactic reaction was again tested and it was alloived to stand in water to 

 which it was accustomed while the other was treated. 



The second isopod, the one giving the most carbon dioxide, ivas placed in a 0.2 mol. 

 solution of calcium chloride until the positive rheotactic tendency was markedly 

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

 again compared in the biometer. 



Rheotaxis test 12:25 p.m. Temp. 20 

 10%+, 90%-; Efficiency, 2.4 

 Tested in Biometer 2:49-3:05 p.m. 

 Little CO2 given off 

 Less CO2 than No. 84 

 Rheotaxis tested 3:50 p.m. 

 60%+, 40%-; Efficiency, 2.0 



Tested in Biometer 4:35-5:12 p.m. 



More CO2 than No. 84 



Survival time in 0.001 Mol. KCN 



1 hour, 35 minutes 

 cf , 5.5 mm. long 



Rheotaxis test 12:00 m. Temp. 20 

 30%+, 60%-, 10%; Efficiency, 2.6 

 Tested in Biometer 2:49-3:05 p.m. 

 Little CO2. given off 

 More CO2 than No. 171 

 Put in 0.2 Mol. CaCh 4:02 p.m. 

 Rheotaxis tested 4:07 p.m. 

 10%+, 40%, 50%; Efficiency, 0.9 

 Taken from CaCU 4:27 p.m. In CaClj 

 25 minutes 



Tested in Biometer 4:35-5:12 p.m. 



Less CO2 than No. 171 



Survival time in 0.001 .Mol. KCN 



2 hours, 55 minutes 

 cf , 6.0 mm. long 



194 



