20 



SilrtT frnitil<'s I liarr imt t<('(ii iDiihr c. /i' liiii . liut |)r()li;i)ily tlicy iiimv 

 1)0 lound cl little ^nniller, Ihougli but rtuely; tlie lurgest ecl.«, on tlic wliolc, 

 whifli I have seen, have beeii silvor eels. Yelloiv jhtiules 1 liave seeii so 

 small tliat it was just possihlc to docide the sex; more difticult is it to .'^tate 

 tlieir limits ujiwaids, as 1 have already meiitioued, because the larger 

 female cels, over e. 78 etm., as a rule, i'orm the transition between yellow ;uid 

 silver eels. 



It wlll be seen that these size limits l'or tlie sexes agree in sucli a way 

 that the supposition that tlie yellow eels are »the young ones' ol' the silver 

 eels lies very near, and the faet tliat no silver eels are found hvw iintlcr the 

 said lengths is, I thiiik, sufticient to warrant our looking upon this suj)position 

 as the only jiossible; there are several other circumstances, however, whieh 

 as deeidedly point at the same solution of the question, and whieh I shail set 

 fortil liere tor further coiiiirmation, viz.: 



1) The greater development of the sexual organs in the silver eels. 



2) The smaller desire for food among the silver eels and the wliole state 

 of their digestive organ during tlie migration. 



3) The periodical oeeurrenee of the silver eels in the waters, their 

 emigration to the sea in summer and, partieularly, in autumn, and 

 the faet that the stoek of eels in our fjords in winter almost exclu- 

 sively consists of yellow eels. 



4) The eonclusioil of the development from yellow eel with eonmieiicing 

 inetallie lustre to the fully developed silver eel without aiiy yellow 

 eolours I have rejteatedly witnessed in eaufs in which I kept yullow 

 eels; sonie of these grew in a few weeks into fully developed sil- 

 ver eels. 



5) W'e lind, in nature, eds whieh in all cliaracters that distinguish silver 

 eels friiin yellow ones (exeejit the size limits dowuwards) form transi- 

 tion stages between both. 



()) Great numbers of silver eels emigrate every year from fresh waters 

 whose mouth is an artitieal loek, where we kuow, therefore, that sil- 

 ver eels never immigrate, fresh waters that always swarm with yellow 

 eels in all sizes whieh wliile they are yellow only emigrate in very 

 small numbers. 

 From the iibove reasons i must edusider it an undouljted faet that the 

 »silver« eels are eels whieh have l'oriiierly beeii »^yellow«, but iiow hejorc the 

 projiagation get a jic'euliar breeding-dress. 



