104 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



contents. Sometimes each fish is individually weighed, 

 but as a general rule all the fish in each cm. group are 

 weighed and the total and average weights determined. 

 In all cases a single fish, or a number of such, are 

 weighed to the nearest gram. It is often difficult to state 

 definitely the condition as regards maturity. As a rule 

 there is no ambiguity iu the case of the males : a male 

 plaice is either mature or immature ; but it is sometimes 

 difficult to say, at some seasons of the year, whether 

 the females are, or are not mature. Mature females are 

 regarded as such in which the ovary extends to more 

 than half way between the first axonost and the root of 

 the tail. 



The question of examining sample catches of plaice 

 purchased from trawlers was considered and decided 

 against. The localities of capture in such cases cannot, 

 as a rule, be accurately ascertained; the fish are often 

 selected, small ones being rejected; the conditions of the 

 hauls from which the fish are taken cannot generally be 

 ascertained ; the fish are usually gutted ; and they may 

 be iced or uniced. No doubt the examination of fish 

 landed at the ports may have a certain value; but it 

 ought to be pointed out that if legislative restrictions are 

 to be based on statistical results all possible trouble should 

 be taken to render the latter as accurate as can be. Now 

 the conditions under which the examination of fish landed 

 at the ports can be carried out are not such as to make 

 the investigation a strictly scientific one. All the 

 measurements of length alone in this report relate to 

 living fish ; and measurements of weight in respect to 

 length relate to ungutted and uniced fish, and are made 

 not later than twenty-four hours after capture. Thus 

 irritating comparisons between " entire " and " cleaned " 

 fish, with the uncertainty attaching to the employment of 



