252 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



These changes of the coefficient are more marked in 

 the case of plaice below a certain size-limit — about 20 to 

 25 cms. — and these are also the plaice which do not 

 migrate so regularly as those of sizes more nearly approxi- 

 mating to that at which sexual maturity is attained. 

 They are, therefore, less able to maintain a certain degree 

 of uniformity in their rate of metabolism by making 

 migrations, than are the larger fishes. 



It is true that the changes of temperature which can 

 be observed, and correlated with these changes in the 

 value of the coefficient are small ones. But it must be 

 remembered that this effect of temperature is an integra- 

 tive one. The change continues to be exerted for rela- 

 tively considerable periods, and its effect is accumulated. 



It must be admitted, however, that the fluctuations 

 in the value of k recorded in this and previous papers, are 

 not easily correlated with concomitant temperature 

 changes. This imperfect correlation is, however, due to 

 the imperfect data at our disposal : the samples of plaice 

 examined are far too few, and the temperature data are 

 also quite insufficient. Smoothed curves, drawn from 

 monthly observations would probably not show the rela- 

 tionship sought. The temperature variations of the in- 

 shore waters of the coasts of Lancashire are certainly not 

 to be represented by the simple harmonic expressions con- 

 sisting of two or three terms only, which such smoothed 

 curves represent. They are relatively complex, and pro- 

 bably incapable of any practicable harmonic analysis ; 

 and it would be results obtained by graphic integration of 

 curves drawn empirically from numerous observations 

 that would alone be susceptible of comparison with the 

 changes of the coefficient k. The relation is only sug- 

 gested here, since it is hopeless to attempt to demonstrate 

 it by the data available. 



