Some physical attributes became unnecessary when the caecilian moved underground, most obviously the legs and the eyes. The caecilian is completely legless, making it look like an earthworm or a snake, and its eyes are weak and covered with skin. Those rings around the caecilian's body are merely folds of skin, not actual body segments, as in an earthworm. A few species can be found in water; like the other amphibians, the caecilians are friends of water, and the largest species of caecilian lives only in the water, swimming around like an eel. Also like the other amphibians, it breathes through a combination of organs--it has lungs, but also breathes through its skin.