1915 



Zeller and Neikirkj on Nereocijstis 



27 



The gas from the pneumatocysts was collected in jars by water 

 displacement. The inverted jars were carefully sealed under water to 

 prevent any mixture of air with the gas. The collections were made at 

 3:00 to t:00 o'clock p. m. and 3:00 to 4:00 o'clock a. m. on different 

 days. In this way the effects of photosyntliesis and nocturnal respiration 

 on the variation of the two gases in question could be determined. Tables 

 I and II contain the results of the analyses for carbon dioxid and oxyo-en, 

 respectively. 



Table I, Shou'ing the analijses for carbon dioxid. 



Average variation of CO, from day to night 2.21%. 



