It may have been removed at the grocery store but if not, here's how to do it. First, cut off the last rib if you can't get a start on it. You'll want to dig in with a blunt object. I use a butter knife. If the membrane is all intact and once you start pulling, it should all just come off in one piece. If not, it'll be more difficult, but just do the best you can. It's not integral that you remove the membrane, it just makes for a slightly easier eating experience. Once it gets going, grab a paper towel and use it to really grasp the membrane. Pull that sucker back.