THE SALMON FAMILY 63 



I have chosen two photographs of scales removed 

 from the shoulder of a fourteen-pound cock fish, caught 

 in the Tay on May 8th, 1911. 



First, let us examine the illustration of the complete 

 scale. 



The smooth portion is that part of the scale which is 

 visible on the body of the fish. The portion showing 

 rings is that part of it which is buried in the skin and 

 overlapped by adjacent scales. The broken edges, and 

 the apparent absence of rings of growth on the smooth 

 part of the scale, are due to the friction to which this 

 portion of the scale is exposed. The centre of growth 

 is seen as a complete little circle ; this was the original 

 scale on the larval fish. Round this centre are several 

 complete rings indicating the growth of the parr during 

 its first year. Outside these rings we have further rings 

 due to the growth of the parr during its second year in 

 fresh water. The lower portion of the second year rings 

 have come on to the exposed portion of the scale, and 

 so have been rubbed down. The rings of growth, so 

 far, are very narrow, as the growth of the parr in fresh 

 water is very slow, but just outside the completion of 

 the narrow rings are seen two broader rings (though these 

 two rings are not nearly so broad as subsequent ones). 

 The two broader rings are due to the increased growth 

 of the smolt in tidal water ; then follow twenty-two very 

 much broader rings, which indicate the growth during 

 the fish's first summer in the sea ; next, six narrow rings 

 for the first winter's growth in the sea ; again, twenty- 



