86 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



Hermes, in behalf of Dr. Syrski, protests against this idea, stating, on 

 the authority of the latter, that the i^ublished opinions of Giinther and 

 Darwin were unknown to him prior to the publication of Jacoby's paper. 

 Up to that time every investigator had choseu for investigation the 

 largest and fattest of eels, thinking that the largest and oldest specimens 

 must have the most highly-developed organs of generation. On Xov. 

 vembr eliO, 1873, Syrski found in the second specimen which he investi- 

 gated — an individual 15 inches long, which is now preserved in the 

 museum at Trieste — a completely new organ, which had never before been 

 seen within the eel by any former investigator, although teus of thousands 

 of eels had been zealously studied.* Syrski published his discovery 

 in the April number of the proceedings of the Imperial Academy of 

 Sciences, Vienna, in 1874.t The most important point of the discovery 

 was stated to be that in all the sj)ecimens of eels in which the Syrskian 

 organ was fouDd, the well known collar- and-cuft' shaped ovary, the 

 female organ of generation, was entirely wanting. It was evident from 

 this that eels were not hermaphrodites. The question now arose, is the 

 newly discovered organ in the eel, in its external form, as well as inner 

 structure, so different from the ovary that it could be considered as a 

 partially developed or peculiarly shrunken ovary ? According to all re- 

 searches which have up to this time been made, there is the highest kind 

 of probability that this newly discovered structure is actually the long 

 sought male organ of generation. The investigator cannot, however, 

 answer this question with complete certainty, since the thing which is 

 most necessary to the solution of this question, namely, the huding and 

 the recognition of the spermatozoa, has not yet been accomplished. 



In February, 1879, Professor Packard announced the discovery of 

 spermatozoa in eels from Wood's Holl, Mass., but soon after declared 

 that this was a mistake, and that he had been deceived by molecular 

 movements among tbe yolk nuclei in the female organs. The discovery 

 of spermatozoa in the spermaries of the conger-eel, recently announced 

 by Dr. Hermes, of Berlin, is, however, suflicient to demonstrate fully 

 the correctness of Syrski's theory. The confirmation in the case of the 

 common eel is solely a matter of time. 



XI. How TO DISTINGUISH MALE AND FEMALE EELS. 

 a. INTERNAL CHARACTERISTICS. — BENECKE. 



The differences between the organs of sex in the eel are well described 

 by Benecke. The ovaries of the eel are two yellowish or reddish- white 



* "I commenced ray investigations," writes Syrski, "on the 29tli November last 

 year (1873), and already in the second eel which I dissected on that day I found the 

 testicles, and therefore a male individual of the eel. I sent in March of the following 

 year (1874) to the Academy of Sciences in Vienna a preliminary communication, 

 which was read at the public session held the I5th April, and printed in the reports 

 of the academy." 



tin 1875, Professor Von Siebold found male eels in the Baltic at Wismar, although 

 this discovery was not at that time made known to the public. They have siuce 

 been found in the German Ocean, in the Atlantic, and in the Mediterranean. 



