REPORT OF COMMISSIONERS OF INLAND FISHERIES. 47 



they were described and named as a separate group. Doubt as to 

 the genuineness of this distinction was first suggested by the German 

 zoologist Carus, nearly fifty years ago. He believed them to be larvte, 

 but referred them to the fishes of the genus Cepola. It was Theodore 

 Gill who first suggested the connection of the Leptocephalus forms 

 to the eel family. Gunther, of the British Museum, believed them 

 to be abnormal forms and incapable of further development, but in 

 1886 Delage settled the question by keeping a Leptocephalus in his 

 aquarium until it completed its metamorphosis into the conger. 

 But we owe it to Grassi and Calandruccio that the development and 

 metamorphosis of many of these Leptocephali were described and 

 referred to the proper adult forms. They pointed out the fact that 

 fertilization takes place only at great depths. They demonstrated 

 that a Leptocephalus possesses as many segments as the adult of the 

 species to which it belongs and identified the larvae of seven different 

 species, including the common eel and the conger. 



Cunningham (1888 and 1891) made some interesting observations 

 on ripe congers. He kept in an aquarium a female conger which 

 was approaching maturity. She ceased feeding in March, and on 

 July 24th a few large but immature eggs were obtained by pressure. 

 Her abdominal cavity was very much distended by the developing 

 ovaries, which grew enormously at the expense of the rest of the 

 body while in the total weight of the fish there was a great reduction. 

 The specimen died September 10 ; her ovaries weighed seven pounds 

 five ounces. In the case of his attempts to obtain ripe male congers 

 Cunningham was more successful. He found a perfectly ripe male, 

 45 cm. long, on December 13. Its eyes were strikingly prominent, 

 and its mouth short and broad. On December 19, among nine 

 congers caught, one 48 cm. and one 66 cm. were males. On Decem- 

 ber 15 he found a small conger dead in another tank; this also proved 

 to be a ripe male; its length was 51 cm. In all these cases micro- 

 scopical examination of the milt showed ripe spermatozoa in most 

 active motion. These had large, well-developed, almost ripe testes. 

 The specimen which was found to be ripe on December 13 was kept 



