THE FRESH WATERS 167 
has yet identified the eggs with certainty, nor 
the very youngest forms of the fish. Minute 
fry are now known, however, which grow into 
3-inch long transparent larve, which feed 
near the surface of the Atlantic by night, and 
sink deeper through the day. Some of these 
““Leptocephalids,’ which had long been a 
puzzle to naturalists, were kept in an aqua- 
rium, and their gradual transformation to the 
elver stage was observed. Then many of 
them were taken at different times from the 
sea, and it was learnt that towards the end of 
summer they begin to undergo a change into 
the “ glass-eel,” or “transparent elver” stage. 
At the same time, apparently, they begin their 
migration towards the shore. The process of 
changing goes on for many months, and, dur- 
ing that time, they do not feed at all, but live 
on their own substance. The elver is not only 
quite different in shape from the earlier form, 
being now a small eel, but it is fully half an 
inch shorter. 
As to the last chapter, it is supposed that 
the silver eels from the British Isles go out 
to the deep waters of the Atlantic and there 
deposit their eggs, which rise to the surface 
and float till they hatch. The eels themselves, 
