THE STORY OF THE COMMON EEL 73 



each their own kind of transparent " Leptocephalus-young- 

 phase," living in but also above the very deep water, in 

 which they are hatched from the eggs of the parent eels. 

 The Leptocephalus-young when hatched, grow rapidly, 

 and ascend to near the surface immediately above the 

 deep water, and are caught at depths of ten to a hundred 

 fathoms. To become " elvers," or young eels, they have to 

 undergo great change of shape and colour, and actually 

 shrink in bulk a process which has now been completely 

 observed and described. It is not surprising that their 

 true nature was not at first recognised. The proof that 

 the silver eels of North and West Europe go down to 

 the 5oo-fathom line off the Irish coast, in order to lay 

 their eggs, is that the Danish naturalist Schmidt and his 

 companions discovered there two years ago, above these 

 great depths (and nowhere else), by employing a special 

 kind of fine-meshed trawling net, many thousands of the 

 flat, glass-like " Leptocephalus-young-stage," or tadpole of 

 the common eel, and traced them from there to their 

 entrance into the various rivers. They showed that the 

 Leptocephali gradually change on the way landward into 

 eel-like " elvers." 



The rivers nearest the deep water, such as those 

 opening on the west coast of Ireland and on the Spanish 

 and French shores of the Bay of Biscay, get their elvers 

 "running up" as early as November, December, and 

 January. The farther off the river the farther the elvers 

 have to travel from the deep-sea nursery, so that in 

 Denmark they don't appear until May. Not the least 

 curious part of the migration of the eel is the passage of 

 the young elvers into the higher parts of rivers and remote 

 streams. They are sometimes seen a hundred miles from 

 the sea, actually wriggling in numbers up the face of a 

 damp rock or wall ten or fifteen feet high, pushing one 

 another from below upwards, so as to scale the obstacle 



