What species of flatworm?

[maggieD]

Found this guy when I was turning over rocks around a little wreck in about 54 ft on the west side of Palos Verdes penninsula. It moved very fast and disappeared after a few moments down a hole in the rock. It didn't seem to have the rhinophore like protrusions most of the flatworms I've seen have.

[scottg]

it looks a little bit like this Enchiridium punctatum I found in the Southern California underwater field guide, but it doesn't look like an exact match.