210 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



Plaice of Age-Group II (that is, over 2 and Tinder 3 

 years of age) are, on the average, about 19'5 cms. 

 (7| in.) long. 

 Plaice of Age-Group III (that is, over 3 and under 4 

 years of age) are, on the average, about 265 cms. 

 (10J in.) long. 

 Plaice of Age-Group IV (that is, over 4 and under 5 

 years of age) are, on the average, about 33 cms 

 (13 in.) long. 

 Fish larger and older than these do, of course, fre- 

 quently occur, but, for all practical purposes, the above 

 groupings represent the plaice of economic importance 

 present in the inshore waters of Lancashire, Cheshire and 

 North Wales. 



(5) Distribution of the Age-Groups on the Fishing Grounds. 



One of the objects for which the ages of the fish 

 samples were determined was that of ascertaining to what 

 extent the various years of life were represented on the 

 various grounds. The material available for the discus- 

 sion of this question is given in the Tables published in 

 former reports on the plaice measurements, but I think it 

 hardly worth while grouping the figures with this object 

 — in the meantime at least. It is doubtful whether the 

 observations are numerous enough for this purpose, but a 

 more serious objection is that the samples received may 

 not have been representative' ones. As a rule, only a part 

 of the catch — from 50 to 100 fish — was sent to the 

 laboratory for examination. The samples sent from the 

 " James Fletcher " seem to me to represent fairly well the 

 distribution of the whole catch made, but this has not 

 been the case with other samples. To find whether the 

 samples are, or are not reliable would mean plotting the 

 distributions against each other — that of the whole catch, 



