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J. E. G. Raymont 



that of July 1944, the average population shows a decline, and seven stations show 

 significant decreases as against four showing increases (Tables IV and VIII). Although 

 it is questionable whether a decline of some 16% in the average population from July 

 1944 to July 1946 is significant, it is at least obvious that the changes in summer 

 population do not parallel those of the autumn, 



SIZE DISTRIBUTION OF SOME BIVALVES 

 An approximate picture of the size distribution of the four common bivalves in 

 North Bay has been obtained. It is likely that, especially where very few small bivalves 

 were taken, the combining of data obtained by the two sampling methods increases 



Table X 

 The size-frequencies of Macoma balthica in North Bay. The figures are averages per 

 m^ based on 10 sampling stations. {Tr. 1, Sts. 1, 2 and 3; Tr. 2, Sts. 2 and 3; Tr. 3, 



Sts. I, 2 and 3; Tr. 4, Sts. 1 and 2)* 



Table XI 

 The size-frequencies of Scrobicularia plana in North Bay. The figures are averages per 

 m- based on 6 stations. (Tr. 1, Sts. 1 and 2; Tr. 2, St. 2; Tr. 3, Sts. I, 2 and 3). The 

 columns on the right of the table show the size-frequencies of small Scrobicularia 



(<10 mm) * 



* Data for November 1943 omitted as sampling methods then not strictly comparable with later 

 samples. 



