No. 526] VARIATIONS IN UROSALPINX 591 



ity (standard deviation) greater than at West Shore 

 and Barnacle Beach, respectively, which were somewhat 

 more sheltered situations. 



Turning to Table X, where the August shells are 

 grouped by years rather than by localities, the A. M. is 

 seen to fluctuate with considerable regularity, reaching 

 in 1902 the highest average ratio. It seems not improb- 



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- 

 (2,147; 



CUM Ml I 



