250 FLY FISHING AND SPINNING 



on the scales of a salmon, and which conclusions in my 

 opinion prevent the life history of the salmon from being 

 accurately determined. 



THE SCALES OF THE SALMONID^E 



These scales are known as cycloid scales. They grow 

 from folds or pockets in the skin, as small thin and trans- 

 parent flaky pellicles of a homogeneous character, invisible 

 to the naked eye. 



They are developed in the early life of the troutlet, or 

 the parr, as soft and pliable additions to the epidermis or 

 outer skin, and as the development of the fish takes place 

 they gradually harden and become as characteristic as shells, 

 nails, claws, hair, and the exo-skeleton coverings of other 

 living creatures. 



The first pellicle forms the nucleus of the scale, and this 

 is being continually added to as the fish grows, each fresh 

 increase extending itself in all directions in the same plane, 

 and slightly beyond the edge of the preceding addition. 



When the scales of a maiden fish are removed, and placed 

 under a lens, each growth appears as a more or less noticeable 

 band extending beyond, but concentric to the edges of all 

 the preceding laminae. 



It will be seen that from these markings we can, until 

 decrepitation has occurred, deduce the past history of 

 the life of the salmon. The width of the protruding 

 edges of each newly formed lamina will depend on the 

 growth of the fish, i.e., on the amount of skin surface which 

 has to be protected ; the rapidity of its growth again 

 depending on the nature and amount of the food it has taken. 



There is but little difference between the skin of the 

 parr and that of the small trout, but the following distinction 

 between the two fish can be made by the fisherman. First, 

 the tail of the parr will gradually assume the forked or lobed 



