These worms have separate sexes.  The eggs and sperm are released at the same time during low tide in the spring.

We have not found a description of the life cycle but similar species produce swimming larvae called trochophores or wheel bearers (referring to the whirling ring of hairlike cilia). Later they begin to take on a more wormlike character before settling down to the bottom.

worm trochophore

terrebellid larvae