Fig. 75.—Section of the body of Gymnotus, showing the position of electric organs. a a, electric organ. Above the organs on each side observe the masses of muscle. b, swimming bladder.)
Date 1892
Source Life in Motion, or, Muscle and Nerve. https://archive.org/details/b21929786
Author John Gray McKendrick
Source: https://commons.wikimedia.org/wiki/File:Life_in_Motion_Fig_75.png

The electric eel (Electrophorus electricus) is an electric fish, and the only species in its genus. Despite the name, it is not an eel, but rather a knifefish. Electric eels inhabit fresh waters of the Amazon and Orinoco River basins in South America, in floodplains, swamps, creeks, small rivers, and coastal plains. They often live on muddy bottoms in calm or stagnant waters.