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730 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Thus but few results have been obtained with great difficulty in all 

 the numerous researches, and the observations have frequently been 

 erroneous. This historical review is also, from an anthropologic point 

 of view, very instructive, showing that not only the masses of the 

 people but also highly intelligent and cultivated men are liable to err. 



I commenced my investigations on the 29th November lastyear (1873), 

 and already in the second eel which 1 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 pre- 

 liminary communication, which was read at the public session held the 

 loth April, and printed in the Eeports of the Academy. 



Having in the course of my investigations met with similar errors 

 regarding the female organs of reproduction in the descriptions hitherto 

 given of them, with the view of rectifying and completing the details, 

 and also for the purpose of comparison with the male organs, I deter- 

 miued to commence by describing the former, i. e., female organs. 



THE OVARIES OF THE EEL. 



These organs (fig. 16), two in number, are ribbon-shaped, with leaf- 

 lets on their outer face, and with transverse folds. In the natural 

 position of the live fish, the one extends to the left and the other to the 

 right of the alimentary tube, following most of its angles nearly the whole 

 length of the abdominal cavity to the place where the dorsal parietes is 

 confluent with the lateral. 



The right ovary commences at a point nearly corresponding to that 

 where on the outside the right pectoral fin ends, and the left ovary com- 

 mences about two centimeters and ends three to four centimeters behind 

 the former. They extend three to six centimeters back of the anus, into the 

 caudal part of the animal's body ; they do not, however, unite in a single 

 body, as some have asserted, but both are toward the end inclosed in a 

 peritoneal membrane, and are separated from each other by the union of 

 these membranes, having each on their inner face an accessory ovary 

 (pars recur rem ovarii). In rare cases is such an accessory ovary want- 

 ing either on the right or on the left side. 



The ovaries in fully-grown eels are in the middle about two centimeters 

 larger, and posteriorly terminate in a thread-like form. They are not 

 smooth on both sides, but have, as was said above, on their outer side 

 numerous transverse folds (fig. 17) full of eggs (fig. 18). 



It is another of Rathke's erroneous assertions, likewise maintained 

 by others, that the genital opening through which the eggs pass out 

 from the abdominal cavity is formed by two holes, a right one and a 

 left one. I have invariably found in all specimens examined a simple 

 hole, which communicated with the right and left half of the abdominal 

 cavity by means of a transverse fissure between the straight intestine 

 and the urinary bladder (fissura recto-vesicalis) and opens in the urethra 

 (fig. 19). 



