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Anoplans and Enoplans: Nemertea

No Common Name (oerstedia Dorsalis): Species Account

Physical characteristics: Oerstedia dorsalis worms are 0.4 to 0.6 inch (10 to 15 millimeters) long and 0.04 to 0.08 inch (1 to 2 millimeters) wide. They have four eyes. Most of these worms are brown to reddish brown and have a white stripe on the back. Some have light or dark brown speckles; some have yellowish dots; some are cream colored without spots; and some have dark bands on a light background. The belly usually is paler than the back.

Geographic range: Oerstedia dorsalis (abbreviated as O. dorsalis) worms live along both coasts of North America, around Iceland, along the western coast of Europe, and in the Mediterranean Sea.

Habitat: O. dorsalis worms live in the sea close to shore. They usually live among algae.

Diet: O. dorsalis worms eat small crustaceans and worms.

Oerstedia dorsalis live in the sea close to shore. They usually live among algae. (Illustration by Emily Damstra. Reproduced by permission.)

Behavior and reproduction: Scientists do not know how O. dorsalis worms behave. The sexes are separate. Fertilization takes place outside the body after the worms release eggs and sperm into the water.

Oerstedia dorsalis and people: O. dorsalis worms have no known importance to people.

Conservation status: O. dorsalis worms are not considered threatened or endangered. ∎



Carson, Rachel. The Edge of the Sea. 1955. Reprint, Boston: Mariner, 1998.

Niesen, Thomas M. The Marine Biology Coloring Book. 2nd ed. New York: HarperResource, 2000.

Web site:

Shimek, Ronald L. "Tie A Yellow Ribbon (Worm) around the Old Reef Rock." Reefkeeping. http://www.reefkeeping.com/issues/2004-01/rs/ (accessed on February 9, 2005).

Additional topics

Animal Life ResourceJellyfish, Sponges, and Other Simple AnimalsAnoplans and Enoplans: Nemertea - Physical Characteristics, Behavior And Reproduction, Anoplans, Enoplans, And People, No Common Name (oerstedia Dorsalis): Species Account - GEOGRAPHIC RANGE, HABITAT, DIET, CONSERVATION STATUS