282 REPORT OF THE COMMISSIONERS OF 



the generation of the eel. It was not, however, until 1850 that Rathke definitely 

 discovered the ovary of a female, and not until 1873 that Dr. Syrski discovered the 

 male organs, and Dr. Jacoby completed the discovery in all its details in 1877; but 

 even this discovery left a big gap in the life history of the eel. Adult eels leave the 

 fresh water and go down to the sea, and elvers, three to five inches long, return in 

 vast numbers from the sea to fresh water, the migration being called eel-fairs, from 

 the Saxon term fare, to travel ; but where they were hatched and how old they were 

 and what became of the parent eels was unknown until 1894, when Prof. Grassi and 

 Prof. Calandruccio, of Rome, cleared up some of these points by discovering the 

 larvae of the eel in the Mediterranean. To put the matter briefly, it is now main- 

 tained, in the light of the discoveries mentioned, that female eels only go into fresh 

 water, while the male eels remain in the sea. Some females do not go to salt water 

 to breed, because they are barren, and they remain permanently, it is assumed, in 

 fresh-water ponds or lakes. What becomes of the adult eels after spawning is not 

 positively known, but the females do not return to fresh water, and it is believed that 

 they die, and possibly both sexes die. 



SILVER EELS. 



Of the silver eels Prof. Grassi says : " As a result of the observations of Peterson, 

 we know now that the common eel develops a bridal coloration or ' mating habit,' 

 which is chiefly characterized by the silver pigment without trace of yellow, and by 

 the more or less black color of the pectoral fin, and finally by the large eyes." 



Peterson's inference that this was bridal coloration was derived from the largely 

 developed state of the reproductive organs and by their ceasing to take nourishment. 

 Dr. Bean records five eels from Great South Bay, which are described as having 

 " large eyes, short snout, and long pectoral fins as compared with the common form, 

 silvery gray above with a clear satiny white abdomen, separated from the color above 

 by the lateral line." They were found " to be males with the generative glands so 

 well developed as to leave no doubt concerning the sex." 



DR. GRASSI SUMS UP. 



Dr. Grassi says further: " To sum up, Anguilla vulgaris, the common eel," [Dr. 

 Meek, Bulletin United States Fish Commission, 1883, after a careful comparison of 

 American {Anguilla chrysypa) and European eels, concludes, ' in American specimens 

 the dorsal fin is proportionately further from the end of snout, making the distance 

 between front of dorsal and front of anal a little shorter than in European specimens; 

 otherwise no permanent difference seems to exist. We should not, therefore, in my 

 opinion, consider the two as distinct species, but rather as geographical varieties of 



