Fig. 102.—Larva of Common Eel, Anguilla chrisypa (Rafinesque), called Leptocephalus grassii. (After Eigenmann.)
In a recent paper Dr. Carl H. Eigenmann has very fully reviewed the life-history of the eel. The common species live in fresh waters, migrating to the sea in the winter. They deposit in deep water minute eggs that float at the surface. The next year they develop into the band-shaped larva. The young eels enter the streams two years after their parents drop down to the sea. It is doubtful whether eels breed in fresh water. The male eel is much smaller than the female.
The eel is an excellent food-fish, the flesh being tender and oily, of agreeable flavor, better than that of any of its relatives. Eels often reach a large size, old individuals of five or six feet in length being sometimes taken.
Species of Eels.—The different species are very closely related. Not more than four or five of them are sharply defined, and these mostly in the South Seas and in the East Indies. The three abundant species of the north temperate zone, Anguilla anguilla of Europe, Anguilla chrisypa of the eastern United States, and Anguilla japonica of Japan, are scarcely distinguishable. In color, size, form, and value as food they are all alike.
Fossil species referred to the Anguillidæ are known from the early Tertiary. Anguilla leptoptera occurs in the Eocene of Monte Bolea, and Anguilla elegans in the Miocene of Œningen in Baden. Other fossil eels seem to belong to the Nettastomidæ and Myridæ.
Pug-nosed Eels.—Allied to the true eel is the pug-nosed eel, Simenchelys parasiticus, constituting the family of Simenchelyidæ. This species is scaled like a true eel, has a short, blunt nose, and burrows its way into the bodies of halibut and other large fishes. It has been found in Newfoundland and Madeira. Another family possessing rudimentary scales is that of the Synaphobranchidæ, slender eels of the ocean depths, widely distributed. In these forms the gill-openings are confluent. Synaphobranchus pinnatus is the best-known species.
Fig. 103.—Pug-nosed Eel, Simenchelys parasiticus Gill. Sable Island Bank.
