Tatle 12. — Chi- square test of the distri"bution between species of first 

 attacks made In each of the four tanks in Experiment I 



Chi-square value of 18.41, with 9 degrees of freedom. 

 (Significantly different) 



Hkble 13. — Chi-square test of the distribution between species of first 

 attacks made in tanks 1, 3, and k of Experiment I 



(T = Tank) 



Chi-square value of 3.64, with 6 degrees of freedom. 

 (Not significantly different) 



17 



