Well, as no one else has replied. Your best bet might be a catalogue book. My local LFS has a book that has any kind of marine animal you could possibly need to ID. It was a small white book, pretty thick. I can't remember what it was. But I used that book to ID my peanut worms.
Sorry I don't have a title or an author, but I'm sure there are a number of books that you can use to ID the alleged hitch hiker.