This is a segmented worm. Kind of ugly, huh?
Windows Original, adapted from Corel Photography


There are two very distinct phyla of worms. The Platyhelminthes phylum is more commonly called flatworms, while the Annelida phylum is also called the Segmented Worms. The differences are found in the names; flatworms are flat, and segmented worms are made of segments!

Flatworms are very colorful, but also very difficult to see because they hide during the day. Flatworms look like elongated pancakes! They feast on ascidians and the occasional invertebrate. Flatworms are no longer than a few inches, but they make up for their size with beauty. Kent's Flatworm is a brilliant red with a white stripe down the middle and speckles of white all around.

Segmented worms are not flat, but look just like your ordinary worm that you find on the sidewalk after a rain. Some of them have tiny hairs that are used for swimming and protection. Some are less than an inch long, while others can grow close to a foot! They aren't pretty like flatworms, and many may say they are just plain ugly, with the exception of the fan worms. These special creatures look like butterflies in the water. Even so, you probably wouldn't want one for a pet!

Last modified December 10, 2004 by Lisa Gardiner.

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Life in the Intertidal Zone

The intertidal zone is the area along a coastline that is underwater at high tide and above the water at low tide. Whether itís a rocky coast, a sandy beach, or a salt marsh, life in the intertidal zone...more

Can there be Life in the Environment of Jupiter?

Jupiter's atmospheric environment is one of strong gravity, high pressure, strong winds, from 225 miles per hour to 1000 miles per hour, and cold temperatures of -270 degrees to +32 degrees (freezing temperature)....more

The possible discovery of Life on Mars

In July, 1996, it was announced that Dr. David McKay, along with a team of scientists at Johnson Space Center (a division of NASA), had discovered possible fossils of bacteria in an ancient rock from Mars....more

The Environment of Saturn

Saturn's atmospheric environment is one of strong gravity, high pressure, strong winds, from 225 miles per hour to 1000 miles per hour, and cold temperatures of -270 degrees to +80 degrees. With winds...more

The Environment of Titan, can there be Life?

Titan's atmosphere is a lot like the Earth's, except that it is very cold, from -330 degrees to -290 degrees! Like the Earth, there is a lot of Nitrogen and other complex molecules. There also may be an...more


Autotrophs are organisms that produce organic compounds from an inorganic source of carbon (carbon dioxide) given a source of energy. If the source of energy is the reactions of inorganic chemical compounds,...more


In the warm primordial ocean, aggregates of amino acids, proteins, and other hydrocarbons coalesced into a form called *coacervates*. Organic polymers such as amino acids will spontaneously form coacervates...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA