282 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1924 



The aim of the former was to obtain a survey of the breeding 

 grounds of the eel, simihir to that I had made of the breeding places 

 of the Gadoids in the Atlantic from Iceland to Spain,^ and the start- 

 ing point in this case was the find, already mentioned, of a full- 

 grown eel larva west of the Faroes in 1904. We hoped by tracking 

 down the larvae in ever younger stages to be able to chart the area 

 or areas where the eel first enters on its existence and at the same 

 time to determine the rate of growth of the larvae and thereby the 

 age of the elvers which appear on the shores of Europe in the spring. 



The second group of investigations was, in contrast to the first, 

 carried out on land in the laboratory. It consisted of a statistical 



119 

 118 

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 IIG 

 115 

 114 

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 112 



III 



in 

 no 



109 

 108 

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 105 

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Fig. I. 



Fig. 1. — Euroix-an eel {Anyuilla vulgaris) and American eel (Anguilla rostrata) 



Number of vertebrae In 266 eels from Denmark {Aiiffiiilla i^tilgaiHn, top grapli) and 

 in 266 eels from Massachusetts, U. S. A. {Anguilla rostrata, lower graph). 



examination of samples of eels from the greater part of the Atlantic 

 area, where fresh-water eels occur. The samples contained as a rule 

 some 200 specimens, and the number of various organs, such as ver- 

 tebrae and fin-rays, was determined in all individuals. I have pub- 

 lished detailed reports of the results of this statistical investigation, 

 and to these I must refer.^ It must here suffice to lay down the fact 



' " The Distribution of the Pelapic Fry and the Spawning Regions of the Gadoids in 

 the North Atlantic from Iceland to Spain" (Rapports et Proems- Verbaux du Conseil 

 International pour lExploration do la Mer, vol. 10, Copenhagen, 1900). 



» " First Report on Eel Investigations " and " Second Report on Eel Investigations " 

 (" Rapports et Procfes-Verbaux du Conseil International pour rExpIoration de la Mer," 

 vol. 18, 1913, and vol. 23, 1915) ; further, " On the Classification of the Fresh-Water 

 Eels (Ati^iiilla)" (" Meddelelsor fra Kommissionen for Havundersogelser, Serie Fiskeri," 

 vol. 4, no. 7, Copenhagen, 1914). 



