182 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



ship, plaice increasing as solos decrease, and vice versa 



(see fig. 4). 



In the monthly variation there is, on the other hand, 

 direct correspondence between the hourly catches of plaice 

 and soles on the banks with the shrimp-trawl (see figs.o, 6), 

 plaice increasing as soles increase, and at approximately 

 the same rate (see fig. 1), though the period of greatest 

 abundance is slightly earlier in the case of soles than in 

 that of plaice, the maximum for soles being in August, 

 while that for plaice is in September. Regarding plaice 

 taken in the channels no very reliable conclusion can be 

 drawn, the data being too scanty, but the greatest catches 

 seem to have been made at the same time as on the banks 

 (see fig. 3). In the case of soles taken in the channels, 

 the curves of average catches with shrimp-trawl and six 

 inch fish-trawl show distinct relation to each other, both 

 as to the position of the maximum catches and in rate of 

 increase (see fig. 2), that is to say, if large soles increase, 

 small soles increase in approximately the same propor- 

 tion. The maximum is somewhat earlier for soles in the 

 channels than on the banks. 



In dealing in the future with separate yearly returns, 

 the curves given here for monthly variation might be 

 regarded as the standard forms, and the curve of monthly 

 variation for any single year, if it differs widely from 

 these standards, might be looked upon as rather 

 exceptional. Of course these curves may differ con- 

 siderably in different localities. 



The tables of monthly averages, and the curves of 

 monthly and yearly variation mentioned above are 

 appended : — 



