2 s 



iuitliois (lo, lliat tlie ycllow ods do uot niigrato at all; tlicy eniigratc tVnm 

 our fjords and heah waters aud immigrate into theui, but ofteii at otlier times 

 and in otlier directions thau the silver eels; several considerable weel-lislicries 

 have lately beeu develojied on tlie basis ol' tliese l'onucrly but little liecdod 

 migrations ol' tbe yellow eels. 



Tliere bas beon considerable doubt l'or soine years al'tcr tbe disuovery 

 of the male eels (1874), wbetlier they were l'ouud in numliers in l'resb water or 

 wbetlier the females were nearly sole masters liere, a question, alter all, of no 

 very great interest, which liad got some scientitic importanee only because 

 their scarcity in l'resb water was supposed to be a jtroof of (heir inability to 

 breed there ; tliey could do so ouly in salt water. 



Already in 1880, however, 0. Hennes proved the occurrence of a mnn 

 ber of male eels a long way up the 'Elbe, but as this did not seem to have 

 convinced r. Siehold that male eels really and ordinarily do oecur in fresh 

 water Hennes further (in »Sitzungs-Berichte der Gesellscliaft uaturforschender 

 zu Berlin 1882« pp. 37 — 38) set l'orth a statement of linds of male eels iii 

 tbe l'>lbe at Wittenberg, i. e. more than 20 Gernian miles from the sea-shore; 

 he l'ound amoug 600 eels on an average 5,2 "/o males, and in order to further 

 remove all doubt he adds; »Dieses Ergebniss ist nicht etwa ein zufalliges, son- 

 dern wurde dureh die im nachsten Jahre fortgesetzteu Uutersuchungen von 

 Neuem als richtig bestatigt«. 



Afterwards several others have showu the oceurrence of male eels in fresh 

 water, and they are known also in our waters. — The piaces, however, where 

 the males are most frequent, are certainly our littlc brackish fjords, as for 

 instance Roskildefjord, where I have found them by far to exceed the fe- 

 males in numbers. (See later on.) 



On Classification and Foreign Species of Eels (Anj/iii/hiJ. 



Of course it is not our northern eels only which get sueh a breeding- 

 dress as that described above; I have seen also at the Zoological Museum a 

 specimeu of Aiiiiuilla ritlf/dria from Egypt, which was a fully developed silver 

 eel, and the breeding-dress, of course, is l'ouud at all piaces where the species 

 occurs; it is not known for ccrtain whether it is found also in the other spe- 

 cies of Amiuilla, represented by such distinct types as Am)mlla snlal and An- 

 fliiilld. lahiata, but it can scarcely be doubted. 



Authors as lileeker and Kaup have set up a number of species 

 of AiKjailUi, which G/inlher has afterwards partly united, uitliout giviug 



