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land— Iceland— Faeroes — Scotland, where a very large number of our stations lay in 1903 

 and 1904. In the Atlantic to the west of this submarine ridge the conditions are different; 

 here the temperature even in the greatest depths is always over 0°, and at our stations 

 on the stretch from the south coast of Iceland to the west of the Faeroes the hydro- 

 grapher of the expedition, Cand. mag. J. N. Nielsen had found temperatures over 5° in 

 1000 meters, and there was further a slight rise from north to south as far as the west 

 of the Faeroes, where our southernmost deep stations lay ' (see chart PI. X, where the 

 temperature curve for 1000 meters depth is drawn). As the single specimen of Leptoce- 

 phaliis brevirostris was just taken to the west of the Faeroes at one of the most 

 southerly of the deep stations, it seemed reasonable to suppose, that we had here the 

 northern limit for the eel larvae and must therefore investigate further to the south 

 in the deep Atlantic water than we had done hitherto, in order to find them 

 in quantity. This became the working hypothesis for the investigations in 1905. 



2. Investigations of the "Thor" in 1905 



During May the "Thor" was engaged with the investigations at Iceland, but towards 

 the end of the month it went southwards to the Hebrides and began from there the search 

 for the Leptocephali. From the Hebrides the course was set to the west and two pelagic 

 hauls with the young-fish trawl were made in different layers at two places (depth: 127 

 and 144 meters) without giving any Leptocephali. Only the young of fish which spawn 

 in shallow water (cod, haddock, whiting, lemon-dab, etc.) were present. At the next 

 station, which lay over the deep water between St. Kilda and Rockall (57°45' N., 9°57' W. ; 

 depth 1150 meters) one specimen of Leptocephahis brevirostris was however taken in 

 a 30 minutes haul with the young-fish trawl (65 meters wire out). In order to find out 

 whether more might possibly be found still further out at sea we went further west in 

 the direction of Rockall as far as 57°47' N., ii°33' W. ; depth 1985 meters and made 

 four hauls there each of one hour with the young-fish trawl in various depths (25, 65, 

 300 and 1500 meters wire out) but without finding any Leptocephali. It thus would 

 seem that we had come too far out and we therefore returned almost to the first 

 station where we had taken the first specimen. Here (57^52' N., 9°53' W. ; depths 1020, 

 1550, 1225, 1470, 1360, 1020, 1320, 1490 meters) several hauls were made with a larger 

 model of the young-fish trawl and 8 Leptocephahis brevirostris in all were taken. We 

 thus had apparently found the right depths for the occurrence of the eel larvae. It 

 also appeared from our hauls that the largest number of Leptocephali were taken with 

 300 meters wire out. 



From this station we went southwards approximately following the lOOO meters curve, 

 which as far as off the northern part of Ireland runs almost due north and south, but 

 then takes a large bend to the west, as a large bank with depths under 200 meters 

 stretches out there from the Irish coast into the Atlantic. All our stations to the north 

 of this Irish bank in depths from ca. 1000 — 1500 meters showed the same features as the 

 first mentioned. Eel larvae were found at all of them but only in small numbers, though 



I As already mentioned we had no stations south of 60° N. L. to the west of 5° W, L. in 1903 

 and 1904. 



