At the very tip of my head (that's the anterior, remember), you will see a flap of skin that hangs over my mouth. It is called the prostomium. It keeps stuff I don't like from getting into my mouth. (Yeah, some things are even gross for worms). It is kind of like your upper lip. (Wanna kiss, baby?) Right under the prostomium is my mouth—you know what that's for. I have a pretty big mouth for a worm. It's big enough to grab a leaf and drag it around.