Polyclad worm swimming

Shot in November 2020.
Polyclad worm free swimming in the water column. Possibly species Pseudoceros mexicanus.
Every 5-10 or so i would see more swimming, at one point three close together. All over the wharf. it was an overcast day with little swell and good water visibility. I could see the surface the majority of the dive ~20ft.
If there are any Polyclad experts out there I would love to collaborate to learn about this behavior further.