SEA-FISHERIES LABORATORY. 223 



considerably above those of the corresponding months of 

 1910. Some other months were a little over, July was a 

 little under, but August had no less than 194 hours 

 recorded, as against 80 hours in 1910, and about 107 as 

 the average of the previous four years. It is clear, 

 however, that this summer and autumn sunshine can have 

 no effect upon the spring phytoplankton. It is, as we 

 showed last year, the March sunshine that may be co- 

 related with that; and any effect of the enormous increase 

 in the August sunshine must be looked for in the autumn 

 and winter plankton— or possibly even in that of the 

 following season. We have seen above that some 

 elements of the plankton were unusually large last 

 autumn, such as the Diatoms. This is well shown by 

 the t)iatom monthly averages per haul in the two years : 



1911. 



August ... 

 September 

 October ... 

 November 



1,998 



928,501 



4,742,791 



506,729 



In both years the autumnal increase begins in 

 September, and reaches its maximum either in that 

 month or in October and falls off in November; but in 

 1911 the maximum is about nine times as great as in the 

 previous year. 



Some of the groups of the zooplankton, notably 

 Cladocera, Polychaet larvae, and Lamellibranch larvae, 

 also show larger numbers this year in autumn and early 

 winter than lias been usual. Whether this is to be 

 regarded as a result of the greal increase in the amount 

 of sunshine las! summer, and if so whether the connection 

 is direct or is in the case of the animals a result of the 

 increased number of Diatoms, we are not prepared to say. 



