This 6" empty tube is from a Spiochaetopterus costarum (Jointed Three-section Tubeworm), found on the beach at low tide.
Here's a Harmothoe imbricata (Fifteen-scaled Worm) just a bit over 2" long, seen at minus tide.
I believe this is Glycera americana (American Bloodworm). It's bristly legs have white bumps on the ends. It was in a tidepool at low tide, was about 4" long, and very active. It kept trying to squirm out of the plastic cup filled with sea water.
Imposible saber de dónde salían, estaban por todas partes
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...