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A Preliminary Account of the Production of Annual 
Rings in the Scales of Plaice and Flounders. 
By 
d 
D. Ward Cutler, M.A. 
Assistant Lecturer in Zoology, University, Manchester. 
With Figures 1-10 in the Text, and Tables I to VI at the end. 
Ir is only within comparatively recent times that it has been proved that 
the otoliths and scales of certain Teleostean fish can be used for the 
determination of their age. 
Rings of growth, as they are called, are produced on these structures, 
and it is by counting the number that the age is ascertained, in much the 
same way as the approximate age of a tree may be determined by count- 
ing the annual rings. 
In May, 1915, I was appointed as a temporary assistant naturalist to 
the Marine Biological Association at Plymouth, and at the suggestion 
of Dr. Allen decided to devote my time to an investigation of the otoliths 
and scales of Flounders and Plaice. My work on the otoliths I hope to 
publish at a future date. 
It has often been asserted that the scales of these fish are of little or 
no value as age determiners. Thus Cunningham in 1905 stated that 
though summer and winter lines of growth are visible, yet “in most 
cases the zones are somewhat difficult to distinguish, and it would be by 
no means easy to form a confident judgment of the age of the fish by 
examination of the scales alone. The conclusion drawn from the scales 
must be confirmed or tested by examination of the otolith.” 
This preliminary account of my work is divided into two parts : im the 
first I hope to show that it is possible to ascertain the age of Flounders 
and Plaice by an examination of their scales, just as accurately as by 
the otoliths, in fact that the otolith growth rings and those found on the 
scales give identical results.* 
* The annual rings on the otoliths of Flounders are not so distinct as those of the Plaice, 
indeed Wallace and other workers on otoliths hold that age determination is uncertain from 
Flounder otoliths. The scales which I have examined from these fish exhibit maxima and 
minima as regularly and distinctly as do those of the Plaice. 
