272 FLY FISHING AND SPINNING 



cannot calculate how many of these rings have been 

 destroyed during the last decrepitations. 



At A in this plate it appears that only five such rings 

 had been added, but at B we can see, if we follow the rings 

 round the scale, that at least twelve others must have been 

 built on the outside ring of this series of five, and that there- 

 fore twelve such rings must have been denuded beyond the 

 outer of the five rings at A by decrepitations. In certain 

 scales where the decrepitation on the outer rings has been 

 excessive and irregular, the new markings which are added 

 to the scale as the salmon recovers its condition are no 

 longer concentric to the former annular markings, or to the 

 nucleus ; they at first appear to fill up the deeper decrepita- 

 tion, and then to be continued as annular bands concentric 

 to one another, and roughly speaking, to the centre portion 

 of the scale. See C., Plate XXX. 



As I have already suggested, the scales are added to only 

 in reply to the requirements of nature. 



The varying number of rings which are formed between 

 the decrepitation of any one season, and between either a 

 recurrent visit on spawning intent, or between a subsequent 

 decrepitation, must frequently preclude any definite 

 conclusion being formed, other than that Nature will create 

 just as many rings and of just so great a width as is necessary 

 to cover and protect the uncovered area of the skin as 

 condition is regained and additional growth attained. 



Referring again to Plate XXX., the decrepitations on 

 this scale at A clearly establish the fact that the salmon had 

 reached a spawning condition, and had probably been for 

 some time in fresh water. Assuming then that this salmon 

 had spawned, or otherwise discharged its ova for the first 

 time in January or February of any year, and that it had 

 descended to the sea in April or May, had recovered, and had, 

 as shown by the decrepitation, again spawned or discharged 



