Gi',6 



THE AMERICAN NATURALIST [Vol. XLIX 



the inbred zygospores produced by lateral conjugation 

 will be more or less correlated than the cross bred zygo- 

 spores produced by scalariform conjugation so far as 

 length and diameter are concerned. 



The value of perfect correlation as measured by the 

 constant (r) is unity, while absence of correlation allows 

 the value to become zero. Length is taken as the subject 

 class (y) and diameter (x) as the relative class in the 

 accompanying tables (VI and VII). 



TABLE VII 



Correlation between Length and Diameter of 200 Zygospores of 





1 



I 



I 



i 



l 



I 



i 



; s I 



i s s 



I 



1 





38.0-39.9 



42.0-43.9 

 44.0-45.9 

 46.0-47.9 

 48.0-49.9 



52.0-53!9 

 54.0-55.9 

 56.0-57.9 

 58.0-59.9 

 60.0-61.9 

 62.0-63.9 

 64.0-65.9 

 66.0-67.9 



70.0-71.9 

 72.0-73.9 

 74.0-75.9 

 76.0-77.9 

 78.0-79.9 























3 



16 

 20 

 25 

 25 



25 

 18 



1 



1 































2 

 2 



4 

 6 



3 

 1 



5 



5 1 

 1 . 









1 







2 



i 



2 

 2 

 "l 



J 6 



\ 



l 

 l 



l 



1 





















1 2 



























Totals 









13 



3s 



46 



6 30 



.. 





200 



While one might infer that the longer a zygospore the 

 greater the diameter, such a condition is not apparent by 

 mere inspection of the tables in either case. Conse- 

 quently on solving the equations we are prepared to find 

 that the coefficients have an extremely low value in each 

 group. 



