212 



\V. C. ALLEE AND SHIRO TASHIRO 



TABLE 4 



Showing the relation between daily variations in carbon dioxide production and 

 rheotactic reactions of isopods Nos. 102 and 12. The amount of carbon dioxide 

 given in ten minutes may be obtained in grams by multiplying the numbers given 

 in the second column by 10- 7 . In the third column + indicates the results are 

 what would be expected from our present knowledge of the rheotactic reaction 

 if there is a direct relation between the rate of positiveness in the water cur- 

 rent and the rate of carbon dioxide production; — indicates the opposite state 

 of affairs. Two oxygen tensions are given; the first being that from which the 

 isopods were taken before their rheotactic test; the second represents that in which 

 they were placed after the carbon dioxide determination. Between testings the 

 isopods were kept in one liter Erlenmeyer flasks which were full of water and tightly 

 corked. 



Isopod No. 102 



Isopod No. 12 



* The increase in negativeness and decrease in indefiniteness indicate an in- 

 creased rate of metabolism. (Allee, '14); 



f No determination due to technical difficulties with the apparatus; carbon 

 dioxide production in all probability very low. 



X More work is needed before an explanation of these results can be offered. 



