THE EEL-FARE 43 



in the discovery of places where the larvae of the eel 

 are actually the commonest fishes towards the surface. 

 Arguing by analogy from the case of other fishes where 

 great swarms of larvae occur near known spawning grounds, 

 Dr. Schmid infers that the birthplace of the eels must lie 

 along the belt of the abundant occurrence of larvae. 



Though absolute certainty is awanting, there is good 

 reason to believe that the eggs are "bathypelagic," that is 

 to say, that they occur floating at considerable depths. 

 This is true of some other members of the eel family, 

 of argentines, and of other deep-sea fishes, and it must be 

 contrasted with cases like the herring, where the eggs are 

 dimersal (i.e. attached to the bottom), and cases like most 

 of our food-fishes, where the eggs are pelagic (i.e. floating 

 at or near the surface of the open sea). 



It is probable that the eggs of eels are hatched in complete 

 or almost complete darkness, at a depth of at least 1000 

 metres, where there is a pressure of about 100 atmospheres 

 and a temperature of over 70 C. Nothing is actually known 

 of the first chapters in the development the forming of 

 the body, the early nutrition all is still in darkness till 

 we reach the stage known as the Leptocephalus. 



For a long time naturalists have known of a thin, trans- 

 parent open-sea creature which was called Leptocephalus, 

 and regarded as a peculiar kind of fish. By careful observa- 

 tions along various lines it has more recently been shown 

 that the Leptocephali for there are several different 

 species are stages in the life-history of eels. We shall 

 only mention two contributions. In 1864, the American 

 naturalist, Dr. Theodore Gill, now a veteran in the ranks 

 of ichthyologists, concluded on anatomical grounds that 

 Leptocephalus morisii was the larva of the conger-eel. 

 In the summer months of 1886, at the marine laboratory 

 of RoscofT, in Brittany, Professor Yves Delage observed 



