TABLE 22 



Arcella polypora. Table showing the relation between the diameter of the shell and 

 the diameter of the mouth in five groups. The unit of measurement is 4-3 m 



Famil}^ ap. 5 



Family ap. 34 



Family ap. 69 



Large specimens from Cold Spring Harbor.. 

 Large specimens from Bloomington, New- 

 York 



MEAN 

 DIAMETER 



11.85 



9.91 



14.00 



25.16 



30.28 



PERCENT- 

 AGE OF 

 DI.^METER 

 OCCUPIED 

 BY 

 MOUTH 



42.10 

 40.90 

 40.53 

 53.65 



48.46 



TABLE 23 



Arcella polypora. Family ap. 34- Correlation table for diameter of mouth and 

 diameter of shell in forty-three specimens. The unit of measurement is 4-3 fi. 

 Coefficient of correlation, 0.861 ± 0.028 



TABLE 24 



Arcella polypora. Family ap. 5. Correlation table for diameter of mouth and 

 diameter of shell in twenty-six specimens. The unit of measurement is 4-3 ju- 

 Coefficient of correlation 0.735 ± 0.061 



56 



