144 The Apodes, or Eel-like Fishes 
may be found in the same waters. It was one of the ideas of 
the Greek to attribute their paternity, as of many other doubt- 
ful offspring, to the convenient Jupiter. The statement that 
they are viviparous has arisen from two causes: one the exist- 
ence of intestinal worms, and the other from the confusion of 
the eel with an elongated and consequently eel-like but other- 
wise very different form, the Zoarces viviparus. The Zoarces 
is indeed, in Germany as well as in the Scandinavian countries, 
generally known as the Aal-mutter, or eel-mother, and thus in 
its name perpetuates the fancy. Even where eels are to be 
found in extreme abundance, and where they are the objects 
of a special culture, like erroneous opinions prevail. Thus, 
according to Jacoby, about the lagoon of Comacchio there is 
an ‘ineradicable belief among the fishermen that the eel is born 
of other fishes; they point to special differences in color and 
especially in the common mullet, Mugil cephalus, as the causes 
of variation 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, Dytiscus reselit, is 
the progenitor of eels, and they therefore call this ‘‘mother of 
eels.”’’ The assignment of such maternity to the water-beetle 
is doubtless due to the detection of the hair-worm, or Gordius, 
in the insect by sharp-sighted but unscientific observers, and, 
inasmuch as the beetle inhabits the same waters as the eel, a 
very illogical deduction has led to connect the two together. 
“All such beliefs as have been thus recounted are due to 
the inconspicuous nature of the generative organs in eels found 
in fresh waters and at most seasons—a characteristic which is 
in strong contrast to the development of corresponding parts 
in fishes generally. Nevertheless the ovaries of the eel were 
discovered, as long ago as 1707, by Dr. Sancassini of Comacchio, 
and described by the celebrated Valisneri (after whom the 
plant Valisnertia was named) in 1710, again by Mondini in 1777, 
and almost contemporaneously by O. J. Miller of Denmark. 
Later the illustrious Rathke (in 1824, 1838, and 1850) and 
also Hornbaum-Hornschuch published the results of special 
investigations, and figured the eggs. But it was only in 1873 
(after several futile endeavors by others) that the male organ 
