294 ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1924 



to endeavor to press forward, the work being done from the trading 

 vessels. We had now, of course, some definite facts to go upon. We 

 knew that the tiny larvae were to be sought during the first half of 

 the year, and the record specimen of only 17 mm. length, already 

 frequently referred to, Avould also be a good guide. I was now able 

 to issue instructions far more precise in character than hitherto, both 

 as regards time and place, and also the depth, to be chosen for fish- 

 ing. Through the very generous cooperation of the East Asiatic Co., 

 of Copenhagen, a considerable number of hauls were taken in the 

 spring and summer of 1914 by steamers of this line on the West 

 Indies route, and these did not fail to produce their result. As early 

 as June, the steamship /Samui and steamship Bintang brought us 

 plankton samples, taken in May and June about latitude 26° N., 

 longitude 55° W., all of which were found to contain larvae of the 

 European eel, for the most part tiny stages. At one of the stations, 

 for instance (station 789, 8/5, 1914) seven specimens of the following 

 lengths were taken: 9, 9, 11, 16, 16, 16, 21 mm., i. e., an average of 

 14 mm., and another (station 793. 11/6, 1914) yielded eleven speci- 

 mens averaging 18.1 mm. in length. 



On returning from the West Indies we set about endeavoring to 

 get another schooner to work in place of the Margreth^^ but theji 

 came the great war, and all plans for further researches at sea had 

 to be laid aside. The work of the trading vessels, however, was 

 maintained during the first years of the war and continued to yield 

 valuable information. In 1915, for instance, we obtained confirma- 

 tion of the fact that tiny larvae occur in summer, and a sample 

 taken at the end of September, 1915, contained eight specimens of 

 about 3% cm. long, i. e., of the same size as those taken by the Mar- 

 grethe in the autumn of 1913. As the war increased in extent, how- 

 ever, our collecting work died out, and several of the vessels which 

 had been assisting us were sunk by submarines. During the next 

 five years, therefore, from 1915 to 1920, the investigations at sea were 

 altogether at a standstill; I was able, however, on the basis of mate- 

 rial from the western Atlantic, to work out a description of the 

 development of the larva? of the two AnguiUa species and a series 

 of other Atlantic muraenoids (1916)." The larvae of the European 

 eel were now known in all stages of development, from that of 9 mm. 

 up to full-grown larvae averaging 7% cm. in length, and in their 

 metamorphosic stages. I was also able to describe the development 

 and metamorphosis of the larvae of the American eel, which proved 

 to be considerably smaller — 1 cm. at least — than that of the Euro- 

 pean, in a fully grown state. 



>" " On the Early Larval Stages of the Fresh- Water Eels (Anguilla) and some other 

 North Atlantic Muraenoids " (" Meddelelser fra Kommlssionen for Havunders8gelser, Serie 

 Fiskeri," Vol. V, No. 4, Copenhagen, 1916). 



