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ratus, which have given specially rich collections, but the eel larva was never found 

 amongst them. In the North Sea Dr. A. C. Johansen has made investigations with 

 Pi:ti-,rsen's young-fish trawl from the "Thor" in the spring and autumn months of 1903— 05, 

 whithout finding eel larvae. I have mentioned these investigations first because to me 

 they indicate so much on account of the great fishing capacity of the apparatus known to 

 me from personal experience, but it is also well-known that both Great Britain and Ger- 

 many have for many years been making extensive collections and investigations in the 

 same direction, which have made us acquainted with the pelagic developmental stages of 

 most of the food-fishes, but never once has the Leptocephalus brevirostris been dis- 

 covered during these investigations. On the other hand, as will be mentioned more 

 particulariy later, the pelagic elvers (i.e. the almost metamorphosed eel larvae) have 

 very often been taken from the Danish, Norwegian, English, Scotch, German and 

 Dutch side during the course of recent years in the neighbourhod of the coasts of the 

 different countries and in the North Sea, and it should be noted also that these elvers 

 are much stronger and swifter in their movements than the Leptocephali. The reason 

 for the facts being as described cannot and should not any more give rise to the 

 least doubt. It can only be, that the eel as larva does not occur either in 

 the Northern Ocean, North Sea, Baltic or on the whole in the shallow 

 coastal waters, where the later developmental stage, the elvers are to be found. 

 Otherwise why should the eel larvae in contrast to the elvers have escaped the 

 many hundreds of hauls which have been made in these waters during the course of 

 years? Even if apparatus of great fishing capacity has not been used everywhere, yet a 

 single specimen must have been taken now and then and if so this would certainly not 

 have remained a secret. And again, why was it, that I could for three years spend 

 months in the collection of pelagic fish young in the coastal waters of Iceland, the Faeroes 

 and in the North Sea without finding the eel larvae there and then with the same appa- 

 ratus could take them in quantifies over the deep Atlantic waters?' Briefly put the fact 

 is, that we can no longer patiently believe that the Northern Ocean, North Sea and North 

 European coastal waters had not been sufficiently investigated. They have been now, at 

 any rate in great part, and if the eel larvae have not been found there, but on the other 

 hand their later developmental stage the pelagic elvers, that can only be, because they 

 do not occur here at this stage of their life, which as we now know is nor- 

 mally passed through pelagically over the Atlantic slope west of Europe, 

 yet been published, it is necessary to give a brief summary of the principal, general con- 



c. Conclusions to be drawn from our discovery of the larvae with regard 

 to the spawning places of the eel 



Important information bearing on this question was collected during our earlier invest- 

 igations with the "Thor" in the Atiantic. As the results of these investigations have not 



I In this connection the hauls at the "Thor's" Stations in the English Channel , West of Ireland and 

 Scotland in shallow water (^less than 200 meters; see situation on the Chart PI. X) are very convincing. These 

 hauls were made at the same period (June 1905) as those further to sea over deeper water, where the eel 

 larvae were found and with the same apparatus (Petersen's young-.Rsh trawl). Nevertheless not a single Lep- 

 tocephalus b7-imrostris was found. In the deep channel of the Skager Rak, where I first thought it possible 

 that the eel might spawn and develop, 1 have lepeatedly endeavoured to find the Leptocephali but without success. 



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