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J. E. G. Raymont 



population than along the rest of the transect, except for one particularly dense patch 

 of 20,000 individuals per m^ in November 1945. On the other hand, the lowest 

 station along Transect 3 had a population almost as great as at higher levels, and the 

 population was maintained over the period investigated. There is an indication that 

 Transect 4 exhibited a slightly different distribution from the other transects in that 

 the highest density of Hydrobia occurred at the uppermost level, and the population 

 fell off sharply on passing down the shore (Table VII). 



CHANGES IN THE POPULATION 



The great majority of the stations showed a decline in total population from Novem- 

 ber 1943 to the following July (Table VIII). This decrease affected most of the 

 members of the fauna (Table IX). The total average population in November 1944 

 was almost identical with that of the previous autumn, but July 1945 showed a decline 

 again. 



