BREEDING 289 



feminine, suggests that, having lived their day, they rub them- 

 selves against rocks, and the pieces scraped off their bodies come 

 to life! According to him, "they have no other mode of 

 procreation." Other authors attributed the birth of Eels to 

 the dews of May mornings, or to the transformation of 

 hairs of horses which fell into the water, and others, again, 

 decided that they sprang from the gills of other fishes. Still 

 more extraordinary is the theory of a certain Mr. Cairncross, 

 which appeared in 1862, this author being convinced that the 

 "progenitor of the Silver Eel is a small beetle!" Even thirty 

 years ago the matter still remained a mystery, and all that was 

 known was that large numbers of adult Eels made their way to 

 the sea every autumn, and that in the spring shoals of elvers or 

 Httle eels, about two and a half inches in length, entered the 

 rivers and made their way upstream. It was very naturally 

 assumed that these elvers were the progeny of those adults 

 that had descended to the sea a few months previously, and that 

 breeding took place in the estuarine waters, a theory shown to 

 be quite incorrect by subsequent discoveries. In comparatively 

 recent years the whole matter has been cleared up by the 

 patient and elaborate investigations of a Danish biologist. 

 Dr. Johannes Schmidt, whose discoveries have provided one 

 of the important biological events of this century. The life- 

 history of the European Eel {A. anguilla) as elucidated by 

 Dr. Schmidt may be briefly described, although consideration 

 of the development and metamorphosis of the curious leaf-like 

 larvae or LeptocephaHds will be deferred until the next 

 chapter {cf. p. 336). 



Two distinct kinds of Eels may be recognised : Yellow Eels, 

 representing individuals in their ordinary feeding and growing 

 coloration, and Silver Eels, which are those in their special 

 breeding hvery. Yellow Eels are found in both salt and fresh 

 water, inhabiting the regions among rocks and weeds close to 

 the shore, in harbours, estuaries, rivers, lakes, small brooks and 

 even isolated ponds. They vary in length from a few inches to 

 five feet or more, and the females grow to a much larger size 

 than the males. Towards the autumn a certain number of 

 Yellow Eels assume their breeding livery and prepare to 

 undertake the journey to the spawning grounds. Of these, 

 the males are generally about eight to ten years old, the females 

 several years older. They cease to feed, the eyes become en- 

 larged, the lips thinner, the snout sharper, the pectoral fins 

 more pointed and blackish in colour, and the yellowish or 



