12 EsDAILE, Scales of tJiree Specimens of Salnio salar, 



in a month or that any definite number are formed in the 

 winter or summer or even during a year. If the number of 

 annuh' were ascertained and then divided by a definite 

 number, as Mr. Mallock suggests, a curious state of affairs 

 would arise, nameh', a different age for the same fish 

 would be shown b\' many of the scales, even when taken 

 from the same position. There is no actual proof that a 

 large number of annuli in each peronidium indicates that 

 the fish has had good feeding grounds and a favourable 

 environment. It is what would be expected, but it is not 

 borne out by the facts. If this were the case, the difference 

 in the number of annuli on the scales of different fish 

 would be to some e.xtent explained, but not the variations 

 in the scales of the same fish. 



Turning to the Tables, it will be seen that it is not an 

 invariable rule that the long axis of the scale has more 

 annuli than those lines at 30'' on each side of it. In fact, 

 in the majority of cases, both in the total numbers and in 

 the numbers per period, the long axis has fewer annuli 

 than lines at 30*^ to the left and right. By comparing 

 the results obtained from the left and right sides of the 

 long axis, it is very astonishing to find how few cases 

 there are where the numbers are equal. Sometimes in 

 one set of scales one side will have, in each period, more 

 annuli than the other ; while in some other cases in one 

 period the left side will have more annuli, and in other 

 periods the right side will have more. The case when 

 one side has, in ever)' period, more annuli than in the 

 other, can be accounted for by the fact that in certain 

 positions on the fish one side of the scales seems to grow 

 more than the other. The whole study of these scales 

 has shown the great irregularity in every particular. This 

 shows that much caution should be used in saying that 

 the scales show this or that. Much more experimental 



