260 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



It was only in a very few cases that any increase in 

 length was detected in fishes liberated during October- 

 December and recaught in January. In April the 

 season's growth begins, and this is most rapid during the 

 months June, July and August. It will be seen that the 

 increase in length during August was apparently nU. 

 That is the average length of the marked fishes returned 

 during that month (and which had been in the sea during 

 the whole season) was apparently no greater than those 

 returned during July. I am quite certain, however, that 

 this is only apparent, and that the fishes received in the 

 laboratory during August were uniformly under- 

 measured. The measurements were made by a laboratory 

 assistant during my absence. It is, indeed, not 

 usually a simple affair to measure a marked plaice sent by 

 post. The fish is often dry, and has to be relaxed by 

 immersion in water for some hours. Then a dead plaice 

 is always shorter than a living one (probably because of 

 the contraction or compression of the inter-vertebral 

 discs). This can be corrected by slightly stretching the 

 fish, and the contraction usually varies from 0'5 to 1 cm. 

 according to the size of the fish. 



It is, however, quite legitimate to " smooth " the 

 curve, which then shows what is probably a little less 

 than the normal rate of increase in length of plaice from 

 month to month throughout the year. In October 

 growth practically ceases. Plaice during the months of 

 November-January usually have very little food in their 

 stomachs, and many are entirely empty during December 

 and January. During those months the weight of the 

 fish decreases. Altogether the metabolism of the animal 

 is greatly lessened. 



The annual rate of increase in length as shewn by 

 the curve is, therefore, about 2\ inches. The annual 



