elusions which can be drawn from the experience already gained. I may remark, that 

 the region dealt with here lies in the Atlantic south of Iceland and west of the Faeroes 

 and Great Britain. 



(1) In shallow water in the neighbourhood of the coasts and on the shallow oceanic 

 banks the water-masses contain only the pelagic young of such species as are born in 

 shallow water. Of the more important of these species may be mentioned: most of the 

 gadoid species (cod, haddock, saithe, whiting, pout), flat-fishes (plaice, dab, lemon sole, 

 long rough dab), herring, sand-eel etc. 



(2) Over greater depths we find only the pelagic fish young which are born in or over 

 great depths, e. g. Molva birkelange, Gadus Poutassou, Gad. argenteus, Gargilius (a 

 new pelagic gadoid), Macrurus spp., halibut, Argentina, Sebastes, Scopelini etc. etc. 



There can naturally be exceptions to these general rules, especially in places where 

 the sea-bottom is very steep, but experience has shown that they are rather few, so few, 

 that they are of no importance on the whole. I had already ascertained this condition ^ 

 in 1903 and both in 1904 and IQ05 I have had its correctness confirmed and supplemented 

 with regard to many other species. Whatever the explanation may be, it is fact that 

 there is a certain relation between the specific distribution of the pelagic 

 fish young and the depth, so that we generally find at any rate quite the great 

 majority of the pelagic young of one or other species over somewhat the same depths 

 as those in which they were born. 



As now all the eel larvae hitherto found have been taken over depths of at least 

 about 1000 meters there is from what has been said above only one possible explanation 

 of this phenomenon, namely, that the larvae are born out there far from the coasts, or in 

 other words, that the eel spawns out in places of at least nearly 1000 meters 

 depths. Future investigations must determine this with certainty 4. 



I An observation on the 1905 cruise during the voyage from Iceland to the Hebrides in May can be 

 mentioned as a characteristic example. For several days we had fished over deep water and not seen any 

 sign of pelagic young of shallow-water fish, only the young of M. birkelange. Gad. Poutassou, halibut, Se- 

 basles. Scopelini etc. etc. The depths varied from ca. 1400— ca. 1000 meters. We then took a station west of 

 the Faeroes Bank (6o°+3' N., io°42' W.) and found the fry of the cod, but we were now over a small new 

 bank where the depth was only 190 meters. At the next station (59°49' N., 8°58' W.) we again had deep 

 water (1150 meters) and here we only found the young of Sebastes, G. Poutassou, Gadiculus and Molva 



2 Compare for example the two charts showing the distribution of the pelagic young of respectively the 

 coastal gadoids (cod, haddock, saithe, whiting, Norway pout) and Sebastes (Skrifter udgivne af Kommissionen 

 for Havunders0gelser, Nr. i, 1904, Tavie III and IV). 



3 I shall refrain from attempting an explanation of this phenomenon, and merely refer to the investiga- 

 tions on the distribution of the cod eggs over the banks and various deep channels at Lofoten described by 

 JOH. HjORT (General Report on the work of the Period July 1902— July 1904, published by the Conseil per- 

 manent international pour l'exploration de la mer, Copenhagen 1905, Appendix G, p. 28—29, Fig. 4). The 

 condition found by Hjort that there are practically no eggs of cod over the deep channels but enormous quantities 

 over the banks, although the channels are but narrow, corresponds in several regards to that shown above. It 

 must be remembered however that the Leptocephali are much older and have thus foi- a much longer time 

 lead a pelagic life than the cod eggs mentioned above. 



That it will for example be fatal for a deep-water fish if its young are carried by the marine currents 

 into shallow water where the normal development is rendered impossible and that the reverse naturally is also 

 true for the shallow-water species need only just be indicated. 



4 In spite of what has been said probably many from theoretical considerations will object, that the eel 



