a slime-coated, eel-like siren salamander (Siren lacertina) with no hind legs, two short front legs, internal lungs, and external gills: it lives in swamps, ditches, and ponds, in the SE U.S.
See mud eel in American Heritage Dictionary 4
noun
A small amphibian (Siren lacertina), found in swamps and shallow waters of the southeast United States, that is eellike in appearance and has only front legs, which are partially concealed by external gills.