306 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



The conspicuous off-shore Westerly migrations of the 

 summer experiments are almost quite absent. Instead of 

 these the migration paths fall into two groups, (1) 

 towards the fishing grounds off the coast of North Wales 

 into the Eed Wharf winter plaice grounds ; and (2) 

 towards the winter plaice grounds to the South and East 

 from Bahama Bank. Twelve fishes have taken the former 

 course, and three fishes the latter : not a very great 

 number, but since these results, again, are entirely con- 

 firmatory of those of the similar experiments of former 

 years, we are thoroughly justified in regarding them as 

 typical and truly representative of a much larger number 

 of migrations. Five other recaptures are represented on 

 the chart as having been made on the Bahama area : 

 these are shown by the arrow-heads without lines con- 

 necting them with the place of liberation. They were 

 plaice recaptured in January and February of 1913, and 

 they are not treated like the rest since it is uncertain how 

 they have migrated : they may, for instance, have 

 travelled North from the Red Wharf Bay area. It is, 

 however, fairly probable that they are fish which took 

 part in the migration that is indicated by the lines and 

 dots, and that they have remained on the Bahama Bank 

 area for a month or so longer without being recaught. 



With the exception of the ten fishes which have made 

 the along-shore migrations, all the others move in such 

 a manner as to support the hypothesis indicated above. 

 Those plaice which have migrated into Red Wharf Bay 

 have moved out of water at a temperature of about 9° into 

 water* at a temperature of about 11°. So also in the case 

 of the plaice migrating into the Bahama, King- William 

 Banks area ; the rise of temperature accompanying this 

 migration is also about 2° C. The adaptation brought 

 about in these winter movements is the same as that 



