582 



MR. J. A. MILNE ON THE 



would account for the marginal thickening if the cells still remain 

 active in fresh water and the scale cannot expand. 



Text-fiij. 101. 





Scale of a 33i lb. Salmon {Sahito salar) cauglit at Povt Gordon, Aberdenshire, on 

 August 19th, 1908. Pveviousl}' marked as a kelt on the Deveron, March 23rd, 

 1908. This tisli had also spawned in the previous year, and the two marks 

 are shown at C and D. The original scale has been lost at the end of the first 

 summer in the sea, and its position filled by a new scale without lines. 



On both text-figs. 100 & 101 two spawning marks are to be 

 seen, but the figures illustrate what I have just said as well as if 

 they had but one mark. Scales which like these show two marks 

 are far from common. The central part of text-fig. 101 is 

 without lines, so that the paiT scale does not show at all. This 

 is because the original scale was lost by the fish towards the end 

 of its first summer in the sea, and the place occupied by it in the , 

 skin pocket was filled by a new scale which, the line producing 



