108 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



or at the mouths of rivers. This statement cannot be exactly clemon- 

 • strated, since among 250 eels, from 11 to 15 inches in length, taken in 

 the vicinity of Cumlosen, I found 13 males or 5 per cent. (Cumloseu is 

 situated in the vicinity of Wittenberg and is at least 120 miles from the 

 mouth of the Elbe). How large the percentage of difference between 

 the neighborhood of the mouth of Elbe and jDlaces situated farther up 

 the stream, as regards the proportion of males and females, may be, I 

 have hitherto, from want of material, been unable to decide. Forty from 

 the Havel at Havelberg (about 20 miles above Cumlosen) were all 

 females. Out of 137 eels taken in the bays at Eiigen, in the Baltic, I 

 found 61 or 44J i)er cent, males, while at Wismar, on the Danish coast, 

 the males only constituted 11 per cent. Whether these facts have any 

 connection with the discovery of the hitherto unknown spawning places 

 of the eels, it is hoped that further observations will determine. 



When Cattle, in his already cited work, gives it as a determined fact 

 that the eels wander into deep water here, in order to let their genera- 

 tive organs attain maturity, which happens in six or eight weeks, and 

 that the old male and female eels, after the reproductive act, die, accord- 

 ing to my knowledge, there are wanting observations which will give 

 this a scientific foundation. What Von Siebold and Jacoby only state 

 as ijrobable appear to him (Cattie) to have become already established 

 facts. 



As far as the distinction between male and female eels by external 

 characters is concerned, the eels sent to me, some time in November, 

 from the coast of Schleswig showed so great difference in color that 

 their sender, the fish-master Hinkleman, was able to decide without 

 difiiculty between males and females. The former were distinguished 

 by a specially brown coloration, while the females, in addition to greater 

 size, almost without exception exhibited a dull steel-gray color. Among 

 the males were found many specimens of 17| inches in length, which I 

 was careful to note because Syrski had only found the size of 16 1 inches. 

 In Comacchio, according to Jacoby, a specimen of 18| inches had been 

 found. 



XIX. Jacoby's tour to Comacchio in 1877, and his conclusions. 



" In the fall of 1877," writes Jacoby, ' ' I undertook a journey from Trieste, 

 by way of Eavenna, to Comacchio; convinced of the difficulty of the ques- 

 tions to be solved by my own previous labors, I had not -great hopes 

 of finding sexually immature eels, either gravid females or mature males. 

 My highest aim was at the beginning to determine the following i)oints : 

 (I) Whether evidences of preparation for breeding might not be found in 

 the eels which were wandering in the fall toward the sea; (II) to what 

 extent eels with the organ of Syrski could be found participating in 

 this migration ; (III) as far as possible to obtain eels from the sea at a 

 distance from the coast in order to compare their organs of reproduction 

 with those of the eels in the lagoons. 



