14 ESDAILE, Scales of three Specimens of Saliiio salar. 



IV. After carefully examining some hundreds of 

 scales I can find no definite or trustworthy distinction 

 between what have been called " main and dui)licate 

 annuli." The annuli branch towards the head and 

 towards the tail, near the long axis or on a level with 

 the short axis {Line AE., Diag. i, Fig. 4). Taking all 

 this into account, I find it impossible to recognise 

 any distinction between different types of annuli. 



This is to be looked u[)on as the beginning of a long 

 piece of work. What I should like to have done, and 

 what I still hope to do, is to carefully examine and 

 measure a whole line or lines of scales from the head to 

 the tail, and also lines from the dorsal to the ventral side, 

 taken at different distances from the head. From this it 

 would be seen, whether the increase in size and in the 

 number of annuli is gradual and comparisons could also 

 be made of scales which were actually found next to one 

 another and not merely of those which have been roughl}' 

 scraped off from certain places. 



No hasty conclusions must be accepted, and it must 

 not be thought that because this arrangement has been 

 found in three fish it is necessarily present in all. It 

 must be remembered that only 60 to 70 scales from each 

 fish have been examined and measured, and the many 

 hundreds of scales on one fish should not be judged by 

 what is found in about sixty taken at random. It is, 

 however, most probable that this arrangement is to be 

 found in all salmon, though whether what now appear to 

 be irregularities will eventually prove to be definite 

 variations can only be shown by further research. 



I must point out that this paper in no way contradicts 

 the general truth of the Scale Theory, as applied to the 

 salmon, worked out by Mr. Johnston and others. Every 



