140 



ISAAC STARR, JR. 



before. The larvae were therefore suddenly subjected to the 

 change of oxygen tension plus the NaCl. 



TABLE V. 



EXPERIMENT 3. 

 Over 50 larvae examined in each case. 



A. Observed i Hour after Return to Sea Water. 



B. Observed 18 Hours after Return to S-ea Water. 



This experiment shows the same diminution of toxicity due to 

 slightly increased oxygen tension. 



IV. In this experiment the oxygen tension was raised to 275 

 mm. before the larvae were introduced, as in the preceding ex- 

 periment. 



