74 



than 50, a few longer than 100 ram. They represent 33 combi- 

 nation-forraulae , or only 14 when those are omitted which were 

 met with only once. I put those 14 formulae and the number 

 of times they were observed together in the foUowing table. 



Only two of these herrings (l b I[ C (2)) show the type cha- 

 racteristic of the herrings of the Northsea; among those which 

 were met only once there are three more having a Northsea-her- 

 ring formula (1 b UB, 1 b I B and 1 a III B). Thus we found 

 araong 100 young herrings of the Zuiderzee (so-called zeebliekjes) 

 only five which might be considered as Northsea-herrings. Of 

 course I do not attach any importance to the circurastance that 

 this number is smaller than is that of the full-grown herrings of 

 the Northsea-type — especially as frora other cons'derations (see 

 p. 66) it might be expected that occasionally a good many young 

 Northsea-herrings mix with those born in the Zuiderzee. 



From the 95 remaining young herrings ten more must be taken 

 away whose formulae do not indicate the Zuiderzee-type; three 

 of these in some respects show the sprat-character (ld III B, 

 2d III B and 2d III C) — however they are not sprats , as at once 

 ma^^ be seen from their short anal fins; a fourth with the for- 

 mula 1 c II B resembles a sprat as far as the first two respects 

 are concerned. The five others are herrings with rather abnor- 

 mal dimensions (4 d III B, 4 c IV C , 2 c IV B , 3d IIÏ B , 

 3 a III C and 3 b II D) — it would be difiicult to explain these 

 combinations. 



ïhe 85"/j| which are left belong doubtless together; there are 

 six of those represented only once , and therefore not figuring 



