Drawings by Professor Grassi, of Rome, of the young of the common Eel and its metamorphosis. All of the natural size. The uppermost figure represents a transparent glass-like creature—which was known as a rare “find” to marine naturalists, and received the name Leptocephalus. Really it lives in vast numbers in great depths of the sea—five hundred fathoms and more. It is hatched here from the eggs of the common Eel which descends from the ponds, lakes, and rivers of Europe in order to breed in these great depths. The gradual change of the Leptocephalus into a young Eel or “Elver” is shown, and was discovered by Grassi. The young Eels leave the great depth of the ocean and ascend the rivers in immense shoals of many hundred thousand individuals, and wriggle their way up banks and rocks into the small streams and pools of the continent.