Types of Roundworms & Flatworms

For such small creatures, flatworms and roundworms can cause a great deal of damage to the human body. Roundworms are most often encountered after the digestion of uncooked meat, which is why restaurants are required to cook meat to a certain degree. Flatworms are not always harmful parasites, but they sometimes use the human body to travel from one area to another.

  1. Planarian

    • Planarian worms, also called Dugesia, are scavengers that also eat tiny protists. These flatworms live in freshwater and are hermaphrodites, which means they have both male and female reproductive organs. Planarians have the ability to regenerate when they lose parts of the body. The planarian flatworm uses a pharynx to suck in food, while the intestine digests anything consumed. Because planarians do not have anuses, there exist flame cells on the lateral edges of the worm that excrete waste.

    Platyhelminthes

    • Platyhelminthes are flatworms that are also known as flukes. Like planarian worms, flukes are also "unsegmented, bilaterally symmetrical worms that lack a coelom but that do have three germ layers," according to the Encyclopedia of Life. Platyhelminthes move either by using circular, oblique muscles to push themselves along or along trails of slime and vibration of the skin. Flukes maintain senses that detect closest sources of light or water movement, called rheoreceptors.

    Turbellaria

    • Class Turbellaria is another type of flatworm. This class contains approximately 3,000 species of worms. Most of these flatworms live in marine environments or on the bottom of bodies of saltwater, also called benthic. Some of these worms, however, thrive in freshwater environments. Worms of Class Turbellaria that live in the sea often are bright and colorful, while terrestial species can be dull and dark. These flatworms reject undigested particles of food through the mouth, while digested waste is ejected through the skin.

    Trichinella

    • Trichinella is a type of roundworm that can cause serious harm to animals that eat raw or uncooked meat. This microscopic parasite, which causes the disease known as trichinosis, is released inside animals when stomach acid "dissolves the hard covering of the cyst and releases the worms," according to the Centers for Disease Control. These roundworms grow rapidly, with larvae that molt up to four times over 30 hours. Female roundworms can grow up to .118 inches, while male worms grow to .06 inches.