Amongst the rocks. Vagueira beach, Portugal.
Possibly Halosydna brevisetosa, will key later
This was commensal in the Rough Keyhole limpet I posted previously.
In a tidepool area.
Red ones slightly striped.
The annelids (also called "ringed worms"), formally called Annelida (from Latin anellus "little ring"), are a large phylum of segmented worms, with over 2,000 modern species including ragworms, earthworms and leeches. They are found in marine environments from tidal zones to hydrothermal vents, in freshwater, and in moist terrestrial environments.They are bilaterally symmetrical, triploblastic, coelomate organisms.They have parapodia for locomotion. Although most textbooks still use the traditional division into polychaetes (almost all marine), oligochaetes (which include...