362 LAKES AND STREAMS 



the Straits of Messina, was the young of the fresh-water eel. It has been named 

 Leptocephalus brevirostris, but this title has, of course, to give place to AnguiUa 

 vulgaris. The specimens taken from time to time at the surface of the ocean 

 were wanderers which, from some cause or other, had been driven out of their own 

 proper zone. As the result of these observations, it is now known that the eel, 

 when full-grown, makes its way down the ditches and streams leading from the 

 ponds it inhabits into the large rivers, and so to the sea, where it descends to a 

 depth of some 560 fathoms. On the way its skin becomes silvery and bright, its 

 eyes grow large and dark, while the reproductive elements (the milt and eggs) 

 develop in both sexes. 



Those eels which do not descend into the sea (for some remain landlocked) 

 never develop reproductive organs. In breeding-eels the males have narrower 

 snouts than females ; the so-called sharp-nosed and broad-nosed eels being merely 

 immature males and females of one and the same species. Eels spawn at great 

 depths in the middle of winter. The innumerable young hatched from the eggs 

 grow to a length of nearly three inches, as the flat, transparent leptocephalids, 

 which subsequently change their shape to become young eels or elvers. Elvers 

 ascend rivers in millions ; " eel-fare " being the English name given to their 

 migration. Some of the young eels climb banks and pass over wet fields till they 

 eventually reach suitable ponds, but others stay in holes in the muddy banks of 

 streams. Their numbers are greatly reduced as the migration proceeds, many of 

 the elvers being eaten by fishes and birds, while vast quantities are caught and 

 sold during the " eel-fare " for human consumption. In warm weather elvers travel 

 by night, but remain in the daytime in quiet gravelly spots under stones or 

 buried in the weeds, and grow larger during their wanderings. When they come 

 upon mill -weirs or other obstructions, they endeavour to ascend in places 

 where water drips through, and are assisted in their efforts at climbing by 

 the stickiness of their skins and the suppleness of their thin bodies; and there 

 are many cases where they have been known to make a circuit over wet 

 ground so as to get round an obstacle or reach other water. Living in the 

 mud during the day and feeding at night, they spend their time in their chosen 

 haunts until old enough to breed, when they endeavour to return to the sea, many 

 of them being caught in the eel-bucks or eel-traps, which in consequence of their 

 habits are always placed with their mouths up-stream. In the cold season they 

 cease their wanderings, moving about occasionally, however, when they are one or 

 two years old, at which time they are caught in large quantities swimming against 

 the current, and sent to fish-breeders, and placed in ponds where they attain 

 their full size. 



The sturgeon (Acipenser sturio), a so-called royal fish, belongs to 

 a very different and more archaic group, although still included in 

 the great division of the Teleostomi. Instead of being clothed with scales, its 

 body is protected by rows of prominent bony plates, and its head is invested with 

 a number of large flat shields of the same substance. This huge fish is an in- 

 habitant of the North Atlantic, and is unknown in the Mediterranean and adjacent 

 seas. On the back it is furnished with from eleven to thirteen rows of bony plates, 

 high in the middle and lower in front, while on the sides it has from twenty-six to 



