Tube dwelling polychaetes look similar to some sea anemones, especially those that bury themselves in the mud. both animals have tentacles on their heads, but how might the rest of their bodies differ?

Sea anemones are marine predatory animals. They are like a terrestrial flowering plant due to their colorful appearance. They are coming under the phylum cnidaria.  

Sea anemones are found in different forms called a polyp. It has a columnar trunk, on the top of the trunk an oral disc and centrally placed mouth. The mouth is surrounded by tentacles.

Sea anemones have a gastrovascular cavity that serves as stomach. This cavity has one opening both meant for mouth and anus.

Sea anemones are capable of changing their shape and lives on the mud, holding it by pedal disc.

Polychaetes are segmented worms. Each segment of the body bears parapodia. It helps them in locomotion. There are different types of polychaetes, tube-dwelling polychaetes are one of them.

Tube - dwelling polychaetes make tubes to protect their soft bodies.  

They don't have parapodia but some special anterior structures for feeding. The tubes are made from calcareous materials.