Nemerteans are a small phylum of opaque, often colourful, cylindrical or flattened, unsegmented worms. They are generally cryptic and found in small numbers, but are ubiquitous in marine and freshwater sediments. They can also be found in plankton, and in moist terrestrial environments.

What is the main characteristic for phylum Nemertea?

Animals in phylum Nemertea show a flattened morphology, that is, they are flat from front to back, like a flattened tube. Nemertea are soft and unsegmented animals (Figure 1). A unique characteristic of this phylum is the presence of a proboscis enclosed in a rhynchocoel.

Where can you find Nemertea?

About a dozen species inhabit freshwater, mainly in the tropics and subtropics, and another dozen species live on land in cool, damp places. Most nemerteans are carnivores, feeding on annelids, clams and crustaceans. A few species are scavengers, and a few species live commensally inside the mantle cavity of molluscs.