Nematoda Characteristics

Symmetry
Roundworms have a bilateral symmetry. This symmetry helps the body be streamlined, allowing the organism to move. In appearance, roundworms are long, pale worms without any segmented lines. However, roundworms are often mistaken for flatworms.

Reproduction
Nematodes reproduces sexually. Some have both male and female sexual organs, but other reproduce using two partners. First, the female carries an ovary in which future worms are present. The male releases sperm cells into the female, and the eggs are carried to the uterus of the worm. When it is time to fertilize, the sperm cells pass through the spicule (needle-like mating structure) to fertilize the eggs inside of the uterus. In hermaphrodites (both sexual organs), these processes functions inside of the worm.

Organs
In the introductory page of Nematodes, they have a present alimentary canal. This is the whole passage along which food passes through the body from mouth to anus (end tip). Nematodes lack a circulatory or blood system.