266 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



well with those of 1905. Plaice practically do not grow 

 at all during the months October to March. At the end 

 of the latter month growth begins. During the months 

 noted, any apparent increase in size of the plaice returned 

 is probably due as much to errors in measurement as to 

 actual growth. At the end of March we begin to notice 

 an increase in length, and during April, May and June 

 the fish steadily increase in length. During July and 

 August the growth is most rapid, and during September 

 it begins to fall off, and in October the plaice have ceased 

 to grow. An estimate of the rate of growth based on the 

 study of a curve constructed from these monthly incre- 

 ments of growth gives us a value of about 2\ inches 

 (6*3 centimetres) as the yearly growth rate of the plaice 

 in the waters of the Irish Sea East of the Isle of Man and 

 adjoining the coasts of Lancashire, Cheshire and North 

 Wales. 



But when the increments of growth indicated by the 

 fishes which have been recovered after one or more years' 

 sojourn in the sea are tabulated, the average growth rate 

 works out at almost exactly 3 inches (7*6 centimetres). A 

 sufficient number of fishes have been recaught, after being 

 about a year in the sea, to render this estimate a very 

 probable one. At the same time it should be noted that 

 these are the larger and more vigorous fishes (as is 

 indicated by their more lengthy migrations), and that 

 they, therefore, grow perhaps more rapidly than the 

 others which have remained closer to their original 

 habitats. 



The cessation of growth in the colder months of the 

 year is not necessarily connected in any way with the 

 spawning habits of the fishes. The great majority of the 

 marked fishes recaptured were immature fishes, and one 

 cannot, therefore, attribute the cessation in growth in the 



