i have a book that has a good section on classification... how to tell apart zoanthid, zoanthigrandi, palyzoa, amphipalyzoa, micro zoa, paligrandi, amphizoa, palycolonia, and like 5 other that i can't remember right now...
i also can't remember where that book might be... lol... but i know that coral atlas has a good polyp section... kinda breaks it down.. but it's been a while since i picked that up and checked it out...