t'A.\AI>f.[\ Jl^HKRlEi^ EXrEniTIOX, lOl/f-lo 



97 



innermost outwards to the margin of the scale, as shown in fiji-. 22 a; in the specimens 

 here in question, however, the arrangement was similar to that shown in fig. 22 h, 

 where, as will be seen, the third summer zone is narrower than the fourth, reckoning 

 from the centre outwards. In 1(110, this peculiar feature was especiall.v marked 



Fig. 22. 



among the 6-ringed fish; in the following year, it was chiefly apparent in the scales of 

 the 7-ringed specimens; and so onwards. The table prepared shows how these parti- 

 cular fisklieep together in one group, with a gradual progression of the group as a 

 whole towards the right of the table.* 



Tablk 1. — Distribution of herring with abnormal arrangement of rings on the scales. 

 Material from grown Norwegian herring, seine caught. 



These observations may best be compared with an experiment whicli has already 

 been carried out in the case of the cod (Winge, XIV). The fish, when caught, are 

 marked with numbered labels, scale samples taken and tbe marked specimens 

 liberated, care being taken to select only fish of unimpaired vitalit.v. 

 After the lapse of some time, some of them are recaptured, and the scales examined, 

 to see whether new annual rings have appeared in number corresponding with the 

 lapse of time between first examination and recapture. Instead of the artificial mark 

 affixed wo have here the peculiar arrangement of the rings as the distinguishing fea- 

 ture of a group whose scales in a given year (1910) numbered six rings in all. It is 

 liardl.v likely that an approximately equal percentage of this group would then, in 

 1911, be fcuind among the 7-ringcd fish, in 1912 among those with eight rings, and so 

 on, up to to the 12-ringed in 1916, if it were not that a new ring made its appearance 

 each year. 



Scales having the appearance shown in fig. 2*2 h were not found, or found in but 

 niiiiiuial (|uantities, among the samples of mature fish until 1910. On the other hand. 



