288 A HISTORY OF FISHES 



sink to the bottom of the nest. The fish now separate, and 

 both at once commence to remove stones from above the nest 

 and to place them on the pile below it, thus loosening a good 

 deal of sand which is carried down by the stream and covers 

 the fertilised eggs. The whole process is then repeated at 

 short intervals until all the eggs have been extruded, when the 

 parents leave the nest. They are by this time so exhausted by 

 the reproductive act that they fall an easy prey to enemies of 

 all kinds, including other Lampreys, the wounds inflicted 

 upon one another during mating are attacked by fungus, which 

 invades and ultimately destroys the tissues, and indeed they are 

 so completely debilitated that recovery is out of the question 

 and every one dies. 



The Common or Fresh-water Eel (Anguilla) is another fish 

 which undertakes a very extensive journey for spawning 

 purposes, from which it never returns, but here the migration 

 is in the opposite direction. Until quite recently the breeding 

 habits of this species were a complete mystery, and some of the 

 older naturalists were driven to advance the most extraordinary 

 and unscientific theories as to the manner in which the Eels 

 propagated their kind. So great was the interest in this matter 

 that, from Aristotle downwards, almost every zoologist pro- 

 pounded his view as to when and where these fishes breed. 

 Aristotle himself, pointing out that Eels had never been found 

 with ripe milt or ova and seemed to possess no generative 

 organs, argued that they must be derived out of "the bowels of 

 the earth," presumably by some kind of spontaneous generation, 

 a view which held favour with the great Izaak Walton. Oppian, 

 as quoted by Mr. Radcliffe, had even more extraordinary 

 views on the subject, but these may refer to the Lamprey. 



"Strange the formation of the eely race 

 That know no sex, yet love the close embrace. 

 Their folded lengths around each other twine. 

 Twist amorous knots, and slimy bodies joyn; 

 Till the close strife brings off a frothy juice. 

 The seed that must the wriggling kind produce. 

 Regardless they their future offspring leave. 

 But porous sands the spumy drops receive. 

 That genial bed impregnates all the heap, 

 And little eelets soon begin to creep." 



Pliny, asserting that the Eel has no sex, either masculine or 



