296 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1924 



at sea. The plans met with great difficulties, but, on the other hand, 

 were strongly supported in various private quarters, both with 

 financial help and in other ways. Particularly effective was the 

 assistance here rendered by the East Asiatic Co., of Copenhagen, 

 which I have already had occasion to mention in a like connection, 

 and whose director, His Excellency H. N. Andersen, placed at our 

 disposal a vessel, fully ready for sea and actually at work, the four- 

 masted motor schooner Dana, of 550 tons, for the purpose of these 

 investigations. 



With the schooner Dana and with the steamship Dana we have, 

 during the years 1920-1922 made hauls at a great number of sta- 

 tions. Most of the stations were situated in the western Atlantic. 

 A great quantity of material was obtained; this has not, however, 

 yet been dealt with in detail, especially the yield of 1921-1922. 

 The mura^noid eggs have not been identified as yet, and I have there- 

 fore been unable to take them into consideration." For the purpose 

 of mapping out the breeding grounds of the eel I have employed — 

 as previously when dealing with the Gadoids — the earliest larval 

 stages, less than 10 mm. in length. These are so tiny that there 

 can be no question of their having moved any considerable distance 

 from the spot where the eggs were spaAvned. 



These tiny larvse were found at a considerable number of stations. 

 On marking these off upon a chart (fig. 5), it will be seen that 

 the breeding grounds of the European eel form a continuous area 

 situated in the western Atlantic between about 22° and 30° N. lati- 

 tude and about 48° and 65° W. longitude. The central portion will 

 be found to lie about latitude 26° N., or approximately equidistant 

 from the Leeward Isles in the West Indies and from Bermuda. 



It is on the 1920 investigations in particular that the chart is 

 based. As to how far the area may vary in extent from one year to 

 another I am unable to say. This much, however, is certain, that 

 tiny larva?, less than 10 mm. in length, have now been found within 

 this area in no fewer than five different years, viz, 1914, 1915, 1920, 

 1921, and 1922. 



The position of the area will be seen from the charts, Figures 5 

 and 6, where it is indicated by the heavily drawn curves, which I 

 have termed the 10-mm. line, as marking the hmits of occurrence of 

 larvse less than 10 mm. in length. Similar lines have been drawn 

 for the 15, 25, and 45 mm. limits, taking all our finds of eel larvae 

 1904r-1921 into consideration. I shall revert later on to these curves 



11 Since it has been questioned whether the ripe eggs of Uie eel contain oil globules, I 

 may mention in this connection that the remnants of the yolk sac found in the earliest 

 larval stages prove to contain a large, quite distinct oil globule (see also fig. 13 show- 

 ing a prelarva). This observation conflrms the conclusion arrived at by T. Wemyss 

 Fulton in 1897 from the study of the ovarian eggs of the eel. 



