Amphiumas have an elongated body, generally grey-black in color. They do have legs, but they are very small; while amphiumas can be up to 116 cm (46 in) long, their legs measure only up to about 2 cm (0.79 in). Therefore, they can resemble eels. They also lack eyelids or a tongue.
Female amphiumas lay their eggs in wet mud, and then remain coiled around them for about five months, until they hatch. The larvae have external gills, but after about four months these external gills disappear and the lungs begin to work. One pair of gill slits, with fully functioning internal gills, is retained and never disappears, so the metamorphosis remains incomplete.
