Filograna implexa (Salmacina incrustans) is a marine species of tubular worm belonging to the class of sedentary Polychaeta of the Serpulidae family. This species is found in the waters of the Mediterranean Sea, the English Channel, the North Sea, the Gulf of Mexico and off the coast of Monzambique, and from South Africa to New Zealand.

The White-tuft Protula, Protula tubularia, is a marine worm belonging to the class of sedentary Polychaetes and the order of Serpulidae which lives in a white calcareous tube and is present throughout the Mediterranean Sea at depths that can vary from 10 meters to over 100 metres. It is a very common annelid.