304 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1924 



Reverting now to the distribution of the various larval stages in 

 the Atlantic, let us glance once more at the charts (figs. 5-7). I may 

 supplement the indications there given by noting here our northern- 

 most, southernmost, westernmost, and easternmost finds of larvae 

 of the European eel : 



Larvcd of the European eel {Anguilla vulf/aris) 



Northernmost find: Lat. 61° 21' N., long. 10" 59' W. {Thar). 

 Southernmost find: Lat. 20° 14' N., long. 57° 03' W. {8S. Tranquebar). 

 Westernmost find: Long. 73° 43' W., lat. 35° 42' N. {Dana II). 

 Easternmost find: Long. 15° 35' E., lat. 38° 07' N. (Thar). 



The result may be briefly exj^ressed as follows: The larvae were 

 found all across the Atlantic Ocean, coastal waters excepted, but 

 only north of the twentieth degree of latitude north. In the eastern- 

 most part of the Atlantic they extend northward beyond the sixtieth 

 degree of latitude. These facts will give an idea of the enormous 

 extent of the area in which larvae of our European eel occur. 



The starting point for the transoceanic migration of the larvae is the 

 area encircled by the heavily drawn line in the charts Figures 5 and 6. 

 If the annual production of eel larvae only occupied a very brief 

 period, say one month, and provided that all individuals came from 

 the same spot and made equal progress, alike in their growth and in 

 their movement eastward, then it would be an easy matter to indicate 

 the position of each particular stage of development in the ocean by 

 curves representing the average lengths of the specimens. As it is, 

 neither of these conditions is fulfilled, and it is difficult, therefore, to 

 draw up a clear and simple chart of the material. After various 

 experiments in this direction I have adopted the method of noting 

 on a large chart the minimum length of the specimens found at each 

 station, these values being then used in constructing the curves shown 

 in Figures 5 and 6. These curves are to be understood as limits of 

 occurrence, i. e., specimens less than 25 nmi. have only been found 

 within the area embraced by the 25-mm. line, and so on. 



The chart gives the main sum of the conclusions to be drawn from 

 the material collected in the course of years. The position of the 

 curves clearly shows that the principal resultant of the movement of 

 the eel larvae from the breeding grounds is directed toward north- 

 east; that is to say, toward Europe. It will be noticed that there is 

 also a certain movement toward the north and northwest. From the 

 data available it is not easy to determine in what direction the main 

 body of the larvae commence to move. From investigations with the 

 Dana, in 1920, it might seem as if the majority started with a north- 

 ward move and did not turn eastward until they had reached several 

 degrees farther north. On the other hand, our investigations of 1913 

 with the Margrethe seem to show that great numbers of larvae can 



