Roundworms are also known as nematodes. They are parasites which infect mammals, including human beings. Roundworms reside in the intestinal tract and can reach lengths varying from 1 millimeter to 1 meter. Roundworms reside as eggs or larvae in dirt and...
Roundworms move by thrashing their bodies back and forth. This creates a lateral movement caused by the thrashing of their muscles. They are not like worms you find in the ground which crawl.
Roundworms cannot crawl. They move through the host's internal environment by thrashing their bodies using long muscles which only the parasite to move laterally.