ALL persons interested in the mystery that until quite recently hung over the life-history of the eel, will find themselves under great obligations to W. Brown Goode for the very able and exhaustive account which he has quite recently published on this subject in the Bulletin of the United States Fish Commission, based upon the scholarly work of Jacoby, and from which we abstract the following. The number of species described by some authors is very large. Dr. Günther would seem to recognise only about twenty-five. Dareste still further reduces the number, making but four species in the genus Anguilla. A. vulgaris, occurring throughout the northern hemisphere in the New and in the Old World, A. mowa and A. marmorata in the Indian Ocean, and A. megalostoma in Oceania, and he further declares that even between these four the boundaries are not clearly defined. The habits of the eel are still not quite understood. So far as is known, it is the only fish, the young of which ascend from the sea to attain an imperfect maturity, and return to the sea to deposit their spawn. The economical value of the eel as a food fish has been now well established, and they easily admit of being artificially introduced into lakes and rivers. The reproduction of the eel has from the days of Aristotle given rise to the most wonderful conjectures and assertions. Leaving out of question such old theories as that the eels are generated from dew, slime, horsehair, and from the skins of old eels, it has been a matter of dispute for centuries whether the eel is an oviparous or a viviparous animal. The reproduction of the eel was a mystery to the learned Greeks. While they knew that other fishes deposited their eggs, no discovery of the eggs of eels was ever made by them. The Greek poets solved the mystery in an off-handed way; for as they were in the habit of assigning to Jupiter the paternity of all children not claimed by earthly fathers, so they attributed the progenitorship of the eels to the same Jove.