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to a greater development of the large tongue in July. How far the tongue extended in a 

 north-easterly direction was not investigated by the "Thor", but there is no doubt that it 

 was now considerably nearer to the Norwegian coast and also extended much further to the 

 north along this. In agreement with this I may also mention that according to friendly 

 information from Dr. Helland-Hansen of Bergen, the Salpse are found in the autumn right 

 in at the coast and in the fjords round Bergen. 



1 have described this drift of the Salps, which I also observed during my cruise with 

 the "Thor" in May — August 1908, because the Atlantic origin of these large and easily 

 recognisable forms is undoubted. But the pelagic young fish which are spawned or occur at 

 the places where the movement is in progress will naturally be involved in this drift. As 

 the streams mentioned pass at least in part over the coastal banks N. and W. of Scotland, 

 on which according to our investigations an immense production of the young of several of 

 the important gadoids and other food-fishes takes place, larger perhaps than anywhere else 

 in Northern and Western Europe ^ (Iceland perhaps excepted), we can understand how they 

 lead to the transport on a large scale of the pelagic fry from the Atlantic to the Nor- 

 wegian Sea (and North Sea), more especially those species whose pelagic stages are of 

 long duration. There is no doubt either, that large quantities of pelagic gadoid fry, of 

 the species spawning in shallow as well as deep water, are carried from the Atlantic into 

 the Norwegian Sea and North Sea (e. g. haddock, coalfish, ling, torsk, Poutassou, blue ling, 

 silveiy pout etc.). If the species spawn in the Norwegian Sea and North Sea as well as 

 in the Atlantic, it is naturally not so easily determined whether the pelagic fry found in 

 the former waters come from the latter, but when we have to do with species which only 

 spawn in the Atlantic there is no difficulty. I may here refer to Charts VII, IV and I 

 which show the distribution of the pelagic fry of the blue ling, Poutassou and silvery pout. 

 These show that whilst in spring the fry of the species mentioned only occur in the true 

 Atlantic west of the line Fseroes — Scotland, the older pelagic specimens were found in 

 summer to the east of this line, and it is to be remarked at the same stations where the 

 Salpae were also taken and not at others. There can thus be no doubt regarding the At- 

 lantic origin of these pelagic fry, nor of the fact that the Norwegian Sea and North 

 Sea receive a large import from the Atlantic, not only of the species which 

 do not reproduce in the former waters but naturally also of those species 

 which according to our investigations spawn on a specially large scale 

 off the North British Atlantic coasts (e.g. haddock, ling, torsk and of the flat- 

 fishes lemon-dab and witch ^; see note 1 below). 



As already remarked, the species in which the pelagic stages are of longest duration 

 will naturally have the best chance of being carried farthest by the oceanic currents^. 



' Amongst gadoids this applies to haddock, ling and torsk (see Charts III , VII , VIII), to a less 

 extent also probably coalfish, further the two true Atlantic flat-fishes lemon-dab (P. microcephalun) and 

 witch (P. cynoglossus) which also seem according to my investigations to have their main centre of pro- 

 duction on the banks on the North British Atlantic coasts, to judge from the enormous quantities of 

 their pelagic fry which occur there. 



- This probably holds good for the coalfish also as is indicated by several things. The reason why 

 I cannot say so with certainty is as already mentioned, that this species spawns so early in the year, 

 that our investigations on the west of Scotland at the end of May and June were too late. 



' "We may also in this connection refer to the eel fishes (e. g. Anguilla and Conger), in which the 

 pelagic stages .have the longest duration of any and whose pelagic fry can be carried passively for 



