BULLETIN OF THE UNITED STATES FISH COMMISSION. 81 



and especially in the common mnllett. Mugil cephahis, as the causes of 

 variations in color and form among eels. It is a very ancient belief, 

 widely prevalent to the present day, that eels pair with water snakes. 

 In Sardinia the fishermen cling to the belief that a certain beetle, the 

 so-called water-beetle, JDytiscus Roeselilj is the progenitor of eels, and 

 they therefore call this 'mother of eels.'" 



IX. — Search for and discovery of the female eel. 



A scientific investigation into the generation of eels could only begin 

 when, at the end of the middle ages, the prohibition which the venera- 

 tion for Aristolte had thrown over the investigations of learned men 

 was thrown aside. With the revival of the natural sciences in the six- 

 teenth century we find that investigators turned themselves with great 

 zeal to this special question. There are treatises upon the generation 

 of the eel written by the most renowned investigators of that period, such 

 as Kondelet, Sahiani, and Aldrovandi. Nevertheless, this, like the fol- 

 lowing century, was burdened with the memory of the numerous past 

 opinions upon the eel question, and with the supposed finding of young 

 inside the body of the eel. 



The principal supjjorters of the theory that the eel was viviparous, 

 were Albertus Magnus, Leeuweuhoek, Eisner, Eedi, and Fahlberg. The 

 naturalists, Franz Eedi and Christian Franz Paullini, who lived in the 

 seventeenth century, must be mentioned as the first who were of the 

 opinion, founded, however, upon no special observations, that the gen- 

 eration of the eel was in no respect different from that of other fishes. 



In the eighteen century it was for the first time maintained that the 

 female organs of the eel could certainly be recognized. It is interesting 

 that the lake of Comacchio was the starting point for this conclusion as well 

 as for many of the errors which had preceded it. The learned surgeon, 

 Sancassiui, of Comacchio, visiting an eel fishery at that place in 1707, 

 found an eel with its belly conspicuously enlarged ; he opened it and 

 found an organ resembling an ovary, and, as it appeared to him, ripe 

 eggs. Thereupon he sent his find, properly preserved, to his friend, the 

 celebrated naturalist, Valisneri, jjrofessor in the university of Padua, 

 who examined it carefully and finally, to his own great delight, became 

 satisfied that he had found the ovaries of the eel. He prepared an 

 elaborate communication upon the subject, which he sent to the Academy 

 at Bologna.* 



At the very beginning there were grave questions raised as to the 

 correctness of this discovery. The principal anatomical authority at 

 Bologna, Professor Valsalva, appears to have sbared these doubts, 

 especially since shortly after that a second specimen of eel, which pre- 



* I fail to find any record of the publication of this paper, except that given by 

 Jacoby, who states that it was printed at Venice in 1710 with a plate, and subse- 

 quently, in 1712, under the title " Di ovario Anguillaruui," in the proceedings of the 

 Leopold Academy. 



Bull. TJ. S. F. C, 81 6 



