1030 
SCANDINAVIAN FISHES. 
supposed to lie young Eels, a mistake against which 
he cautions his readers, but which often crops up, even 
in modern times. He believed that Eels were born of 
worms generated in the sea by decaying weed and on 
the shores of fresh water by mud under the influence 
of heat". According to Pliny 6 the Eels rub themselves 
against the rocks, and what they thus scrape off their 
bodies comes to life. According to Rondelet 0 even 
Athenteus and Oppian (2nd and 3rd cent., A. D.) had 
seen Eels knot themselves together in bunches; and 
they believed that the slime the Eels thus pressed out 
of one another’s bodies received animation. The old 
tale of the Eelpout ( Enchelyopus , see above, p. 607) 
as “Eel mother” can be traced in literature back to 
Albektus Magnus. With these conjectures the Eel 
question was dismissed throughout the Middle Ages; 
and the founder of modern ichthyology, Artedi, re- 
frained from touching the point in his writings' 7 . Ti- 
selius, a Swedish rector and a contemporary of his, 
had, however, published at Upsala in 1723 an “ Ut- 
forlig beskrifning ofver den stora Svea och Gotlia Sjon 
Wdtter ”, where he relates (p. 113) that “in several 
Eels, close to the small of the back and the spine, 
has been seen a fine and handsome roe of a reddish 
appearance”. This observation probably refers to the 
kidneys of the Eel, but perhaps to the true ovaries. 
The first discoverer of these may- thus have been a 
Swede; but in scientific literature the Italian MondinP 
and the Danish naturalist 0. F. Muller 7 are generally 
mentioned as rivals for this honour. The ovaries were 
more thoroughly investigated by RathkiT and Hohn- 
baum-Hornschuch \ The male organs of the Eels 
were not discovered until more recent times. Rathke 
indeed speaks in several passages’ of such organs, but 
whether he referred to the true testes, or had ac- 
knowledge of their structure, seems more than doubt- 
ful, for he so expressly states that they are without 
efferent duct. SyrskP was the first to publish more 
accurate information of these organs, and since then 
B roc ii 7 and Ryder/ have been the principal contri- 
butors to the elucidation of questions connected here- 
with. 
The first observation from which we can derive 
a positive opinion as to the breeding of the Eel, is 
old enough, even in a literary sense. Aristotle was 
quite aware that the Eel goes out to sea, but he ex- 
pressly denied that these wanderings were due to sexual 
instinct, the Eel being destitute, in his opinion, both 
of semen and ova. From the middle of the 17th cen- 
tury, however, it has been known that the Eel breeds 
in the sea. We are told by Franciscus Redi “Now 
there are other fishes that pass the greater part of their 
life in fresh water, but resort to the sea for the pur- 
pose of disburdening themselves of their seed. Thus 
I have arrived, by means of numerous and long con- 
tinued observations, at the conclusion that year by year, 
as soon as the rainy season sets in about the month 
of August, especially on dark and cloudy nights, the 
Eels repair in great numbers from rivers and lakes to 
the sea, where they deposit their germs. The small 
Eels born of these swim up the mouths of the rivers 
into fresh water earlier or later, according as the 
weather is more or less severe, towards the end of 
January or just in the beginning of February, so that 
the migration is commonly over by the end of April. 
They do not arrive in one body, but in several de- 
tachments and at varying intervals. They come in 
such numbers that some fishermen whom I cominis- 
“ There are several mediaeval receipts for the breeding of Eels by laying two moist sods with the grassy sides together. 
b Hist. Mundi, Lib. IX, cap. 50. 
c De Pise, fluv., p. 199. 
d Linnaeus ( Syst . Nat., 1. c.) based his opinion on Fahlberg’s communication to the Swedish Academy of Science in 1750 of the 
discovery of young in the intestine of Eels, a repetition of the old confusion with intestinal worms. 
e De Angaillae ovariis, communicated to the Academy of Bologna in 1777, but not printed until 1783. 
f Underbrochne Bemiiliungen bei den Intestinalwurmern, Schr. Berl. Ges. Naturf. Freunde, vol. I, 1780, p. 204. 
g Beitr. Gesch. Thierw., 2:te Abth. (Schr. Naturf. Ges. Danzig, Heft. Ill), pp. 121, 161, 175; Weibl. Geschlechtw. Aal., Arch. 
Naturg. 1838, p. 299: Bemerk. liochtr. Aal , Arch. Anat., Phys. 1850, p. 203. 
h De Anguill. sem et gener., disp. G-reifsw. 1842. 
i Beitr., 1. c., pp. 183, 186, 196. 
I Uber die Reproductions- Or gane der Aale, Sitsber. Akad. Wiss. Wien, LXIX, i (1874), p. 315. 
k Mith. Zool. Stat. Neap., Bd. 2, p. 415. 
1 Bull. U. S. Fish. Comm., 1885, p. 1. 
m Francisci Redi, Opusculorinn pars tertia, sive de animalculis vivis quee in corporibus animalium vivorum repermntur, observationcs. 
Ex Etrusci Latinas fecit Petrus Coste, Lugd. Batav. 1729, p. 99. 
