Earthworms and roundworms are often mistaken for each other. While they may look similar to the eye, an individual would have to look deep inside these worms to see how they are really different.
Earthworms and roundworms can live in fresh water, salt water and soil. Roundworms can also be found living in hosts such as humans or animals, as many of them are parasites.
An earthworm has a full digestive system and its diet consists of dirt and plant matter. A roundworm has a definite digestive system and its diet consists of other animals and plants.
An earthworm has blood, blood vessels and five working hearts. A roundworm does not have blood, blood vessels or a heart.
The earthworm and roundworm have no respiration system. Both types of worms take in oxygen through the skin and give off carbon dioxide.
The roundworm is round, thin and smooth. The roundworm can grow up to four feet long. The earthworm is brown and its skin is always moist. The earthworm can grow up to eight feet long. Both types of worms have bilateral symmetry.