204 MICHLGAN ACADEMY OP SCIENCE. 



The correlation between color and size (as expressed by the outer diam- 

 eter) in Arcella shells was studied. The value of the coefficient of corre- 

 lation in this case was 



r = .012. 



This is a very low value and indicates that there is practically no 

 correlation between color and size in Arcella shells, Avithin the size limits 

 of the series of shells studied in this work. 



A full discussion of these results has appeared elsewhere. 



