EEL AS. •l, Ger. Aa/). An elongated, ser pent shaped fish of the order Apodes (q.v.) ; soft-rayed, without ventral fins, and having the long dorsal tin eoniluent with the anal around the tip Of the tail. The skin is smooth and exceed ingl• slimy and slippery. it may contain small scales, or scales may be entirely wanting. The vertehrw, because of the elongated form of the body, are very numerous. The best-known eels are the fresh-water eel (Anguilla a/wan/I, be longing to the family Auguillidw. and the scale less conger eel (Lriitoeciihn/us conger), of the family Leptocephalid.e. The common fresh-water eels. which have minute scales imbedded in the skin. occur on both sides of the Atlantic and as cend rivers and live there for the most part, returning to the sea in the autumn. or they may bury themselves in the mud during the winter. Sometimes they are dug out of the mud of river banks where large numbers of them may be found congregated together. Their activities and mi grations seem to take place mostly during the night. They frequently make excursions on land in the moist grass for considerable distances, the purpose of which is not well understood.
The reproduction of the eel has excited the attention of naturalists since the days of Aris totle. In 1763 an eel-like fish, taken off the English coast by William Morris. was named Leptoeephalus. Numerous specimens have since been obtained all over the world and the family Leptoeephalidre has been erected to contain the various species which have been described. It has been suggested that. the Leptocephalithe are larva of eels, and this has been shown by Delage and by Grassi and Calandruecio, as a result of breeding experiments, to he the case, for as they developed they revealed all the characters of eon ger eels. Eventually Grassi showed that one of these Leptoeephali (Leplocephalus brerirostris), characterized by its small size. short body, and absence of pigment. is the young or larval stage of the common eel. The discovery of Grassi (1893) was facilitated by the peculiar whirlpool currents in the Straits of Messina which occa sionally bring bottom organisms to the surface, and since the young eels are found at the surface with well-known denizens of the deep sea. it is
concluded that the young develop at great depths ( 1500 feet). From the depths are brought also adult male and female eels with ripe eggs and sperm. The entire reproductive history of the eel may now be given as follows: Eels that descend from the fresh water to the sea do so during the months October to January, and in a sexually immature condition, as long been known. They go to the depths and live there for eight months or snore, during which time they become sexually mature. The eggs are fertilized in August and the following months, and being heavy they tend to keep to the bottom, Nvliere, on account of the low temperature. they develop slowly. I .:111'0. from these eggs are found in spring and summer. In the autumn and winter, October to February. these young eels pass from the sea into fresh water in great numbe•s—im migrations which have long been known as 'eel fares': the fish themselves. now over a year old. are called 'dyers.' 1'wo years then intervene between the descent of the parent eels, mid the of their progeny. The old fish seem lo return to the fresh water irregularly at various months of the year.
Eels are very voracious and will eat the most varied sort of food. They grow to a length of four to five feet. Although much prejudice against them exists in certain regions, they are important food-fishes, and are much eaten both in Europe and America. By ninny they a re thought to be poisonous, a notion which may have its origin i 11 the wcll-knowu fact that eel's blood transfused into the system of higher vertebrates is very poisonous; hut the same is true of the blood of other animals, though, perhaps to at smaller decree. Anguilla. of which there are sev eral species, is found ill all warns seas except the East Pacific. Eels are trapped by eel-pots and baskets and are extensively speared. Sec CON GER; ELECTRIC DISHES; and Plate of EELS, CONGERS, AND MORAYS.