Flatworms | Roundworms | |||
A flatworm has a thin, dorsoventrally flattened body. | Roundworms are more cylindrical in shape and tapered to a fine point at one end. | |||
Flatworms are covered with cilia, hairlike growths. The gliding locomotion of a flatworm is powered by many tiny cilia on the outer surface of its body. | Roundworms have a rigid outer covering called a cuticle that they shed repeatedly throughout their lives and as they grow. Roundworms have longitudinal muscles that they contract to bend their bodies in a thrashing motion. | |||
Flatworms generally live in bodies of water. | Roundworm species can live either on water or in soil. | |||
Flatworms are acoelomate, which means they do not have a body cavity. | Roundworms are psuedocoelomate, which means they have a body cavity between their mesoderm and endoderm layers. | |||
The flatworm has a gastrovascular cavity, with only a single opening that functions as both mouth and anus. | The roundworm has a complete digestive tract, with two separate openings for the mouth and anus. | |||
Some flatworm species are also hermaphrodites, meaning they contain both male and female sex organs. | Roundworms have distinct males and females. |