45 



For the purpose of age determination the scales of the long 

 rough dab are very similar to those of the lemon dab. The con- 

 centric ridges are wide apart in that portion of the scale formed 

 during the summer, and approach closer to one another in the 

 slower growing period of winter. The otoliths also are clearly 

 marked with zones of growth, and have been used to check the 

 results obtained from the scales. 



The age composition and the average size and range in size 

 in cm. of the fish examined were as follows : — 



An attempt has been made to calculate the growth of the long 

 rough dab from the scales. Although the end of each }' ear's growth 

 is not so clearly marked as in the scale of the lemon dab it can be 

 fixed with a fair amount of accuracy, especially if when examined 

 under the projection microscope the scale is throv*^n slightly out 

 of focus. 



A summary of the calculations made is here given : — 



Average Size at end of Year's Growth. 



