638 NATURAL HISTORY OF AQUATIC ANIMALS. 



applied himself with great zeal to the task, the results of which were published in May, 1777. 

 The paper is entitled "De Anguiilse ovariis,"' and was published six years later in the Trans- 

 actions of the Bologna Academy.^ Mondini was satisfied that the supposed fish which Vallisneri 

 described was nothing but the swimming bladder of the Eel in a diseased state, and that the 

 bodies supposed to be eggs were simply pustules in this diseased tissue. In connection with this 

 opinion, however, Mondini gave, and illustrated by magnificent plates, a good description and 

 demonstration of the true ovaries of the Eel, as found by himself. This work, which in its 

 beautiful plates illustrates also the eggs in a magnified fold of the ovary, must be regarded as 

 classical work, and it is an act of historic justice to state that neither O. F. Miiller nor Rathke, 

 but really Carlo Mondini, was the first discoverer, describer, and demonstrator of the female 

 organs of the Eel, which had been sought for so many centuries.^ 



Three years later, entirely independent of Mondini, the celebrated zoologist Otto Friedrich 

 Muller published his discovery of the ovary of the Bel in the "Proceedings of the Society of 

 Naturalists" at Berlin.' 



The discovery of Mondini was next specially brought into prominence through Lazzaro 

 Spallanzani. This renowned investigator, in October, 1792, went from Pavia to the lagoons of 

 the Po, near Comacchio, for the sole purpose of there studying the eel question. He remained 

 at Comacchio through the autumn ; he was, however, unable to find anything that was new 

 regarding the question, but in the report upon his journey of investigation he entirely threw 

 aside the discovery of Mondini, and announced that the ovaries discovered by this authority were 

 simply fatty folds of the lining of the stomach.* 



"It was without doubt this absolute negative statement of such a skilled investigator as 

 Spallanzani which for a long time discouraged further investigations on the eel question, and 

 allowed what had already been discovered to be regarded as doubtful, and finally to be forgotten. 

 So when Professor Eathke, of Konigsberg, in his assiduous labors upon the reproductive organs 

 of fishes, in the year 18i!4, described the ovaries of the Eel as two cuff-and-coUar shaped organs 

 on both sides of the backbone, and in the year 1838 described them as new, he was everywhere 

 in Germany (and to a large extent to the present day) regarded as the discoverer.* The first 

 picture of the ovary after that of Mondini, and the first microscopical plate of the egg of the Eel, 



iDe Bononiensi Scientiarom et Artium Institute atque Academia Commentarii. Tomus VI. Bononise, 1783, pp. 

 406 et seq. 



^Prof. G. B. Ercolani, of Bologna, and also Crivelli and Maggi, in their essays published in 1872, have rightly 

 stated that Mondini's priority of discovery has been overlooked in Germany. Neither Eathke nor Hohnbauin- 

 Hornschech nor Schliiser have mentioned his work. S. Nillson, in his "Skandinavisk Fauna," 1855, says nothing of 

 Mondini. He mentioned as the first discoverer of the ovaries O. F. MtlUer, while Cuvier, in his "Histoire Naturelle 

 des Poissons," assigns the honor rather to Eathke. Th. von Siebold is the first to announce in his work, published 

 in 1863, "Die Susswasserfisohe von Mitteleuropa," page 349, that Mondini, almost contemporaneously with 0. F. 

 Muller and independently of him, discovered the ovaries of the Eel. The error, as was discovered by Italian zoologists 

 later than by those of Germany, arose from the fact that the announcement of Muller's discovery was printed in 1780, 

 while that of Mondini's, which was made in 1777, was first printed in 1783. 



'0. F. MfiLLER: Bemuhungen bei den Intestinal-wiirmern. Schriften, Berlin. Gesellschaft, i, 1780, p. 204. 



■"'Eathke, who first, since Mondini, has in detail described (1824, 1838, and 1850) the ovaries of the Eel, is con- 

 sidered by some to have recognized them ; but this, however, is not true, the additions made by him to Mondini's 

 description being to a great extent erroneous. It is not true that the transverse leaflets are wanting in the ovaries 

 of the Eel, as he asserts in his last work, contrary to his former description, which was probably b.ased on the law 

 of analogy, and that thereby they are distinguished from those of the salmon and sturgeon. It is not true, what 

 Eathke likewise asserts, that the genital opening of the Eel consists of two small canals, for I have invariably only 

 found one, which opens in the urethra. Eathke has certainly described the eggs quite exactly, distinguishing the 

 larger whitish ones, having a diameter of about one-fifteenth of a line, and the smaller transparent ones, with the 

 germinal vesicle inside ; but Mondini likewise says: " inmimeras sphcBvulas minimas, mqttalea, pelluddas, divisaa tamen, 

 qucein centra maeulam ostendeiant, ece. vidi," thus showing the true nature of the ovaries and the eggs, and contrasting 

 them with the fatty formation and with the ovaries and eggs of other osseous fish." — Syrski. 



