FISHES 179 



or putrified bodies of eels ; others that they were 

 formed from dew and honey. The greatest importance 

 was always attached to their intestinal worms, which 

 were claimed to be their young. 



We should know that our river-eels are all females, 

 and that the males, never more than half a yard long, 

 live exclusively in the sea or in brackish water. Every 

 autumn great swarms of female eels, that have passed 

 their fifth year, travel to the sea, while others remain in 

 the fresh water, and settle down to their winter sleep 

 in the mud. The former make steadily down stream ; 

 never on clear nights, and preferably when a storm 

 darkens the sky, and the water is lashed by it. When 

 they reach the sea, the males join them, and the eggs 

 are laid in the deepest parts of the sea, and fertilised by 

 the male. The young eels issue from the eggs, but they 

 are so unlike the old ones that they have always been 

 described they have long been known as a particular 

 species of fish. 1 They are so completely transparent 

 that one can read any kind of print through them, and 

 they are not noticed in the water, as a rule ; in shape 

 they are flat and lancet-shaped. Gradually, in the 

 course of a year, they become darker and serpent- 

 shaped, and then from May to July the young 

 animals travel up stream. They may be seen in count- 

 less swarms in the under-current of rivers. It is said 

 that in the year 1667 three million pounds of them were 

 taken in five hours in the Arno at Pisa. In the Elbe 

 a black streak has often been seen moving upwards 



and Calandruccio have shown that the Leptocephalus 

 brevirostris is the eel in its early form. 



