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Marine Worms - Nemertea (Ribbon worms or Proboscis worms)

Nemertea is a phylum of invertebrate animals also known as Ribbon worms. They are also known as Proboscis worms because they can extend a proboscis to capture their food. There are about 1,400 species of ribbon worms nearly all of which are found in oceans around the world. Most species live on or in the sea floor, with many species found in brackish water in estuaries, and even some freshwater and land-based species. Their habitats include - in and among seaweeds, rocks, mussel and barnacle beds, under shells or buried in mud, sand, or gravel substrates.

They have a similar appearance to flatworms although they usually are larger, thicker-bodied, and longer. The largest species may grow to several metres or more but some species are less than 20 cm in length, and some just five millimetres long. Most species are pale, some are brightly coloured with patterns of yellow, orange, red and green.

Purple ribbon worm
Image © Gary McDonald Flickr


Nemertea have long, thin, unsegmented bodies. They have no true head and have an eversible (can be turned inside out) proboscis which is used for catching prey. They have a digestive system which includes a mouth, oesophagus, stomach, intestine and anus.

Most nemerteans are carnivores and predators, although some are scavengers and others are herbivores. They catch their prey with their proboscis which is wrapped around the prey which is then stabbed until it is dead. In some species the proboscis has a sharp part attached (a stylet). In some species the stylet contains a poison to kill prey faster.

Mot species have males and females which release sperm and eggs into the water. Only some species produce larvae, the majority produce offspring which resemble the adults.

Pink ribbon worm
Image © Eunice Khoo Flickr




Red ribbon worm
Image © Ria Tan

Milky Ribbon Worms (Cerebratulus) with Tidepool Tim of Gulf of Maine, Inc.
Learn about this unique nemertean worm that can be found in tidal mud and sand. Milky Ribbonworms can reach
3 or 4 feet in length and have an interesting proboscis for feeding. See two specimens collected by
Tidepool Tim of Gulf of Maine, Inc. Biological supply.

Nemertean attacking Polychaete
There are two nemerteans a small one and a large one and the large one uses its proboscis to attack
the polycheate which is eversing its pharynx. All of the animals are from the Puget Sound.

Next: Echiura  ...   


Polyclad Flatworms
Segmented worms
Arrow worms
Acorn worms
Horseshoe worms
Ribbon worms
Peanut worms


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