17. ("Memory of the dance that none of them had attended shook all four boys convulsively")

Within this one quote lies many important notions relevant to the progression of the story.  The loss of innocence in this story, as previously mentioned, had led the boys to a tipping point.  Now, Ralph and his gang were left to come to grips with the events of the night prior, which included most notably the killing of Simon in a "dance", which was really more of a mad killing frenzy.  The air created through this quote is one of conflicting emotions, mostly denial.  Unlike the savages, Ralph's group had sworn that they were going to stick with the morals instilled in them back at home.  Meanwhile, just the night before, they had all participated in the murder of the most innocent character in the novel.  Predictably, Piggy went with the approach of complete denial, while Ralph remained realistic.  In front of Samneric, however, who had presumably missed this ritual, he also begins to fall into a state of denial.  All of the boys present in this scene had in fact attended the "dance", and they all felt terrible about it.  The death of Simon represents a turning point in the book, and in this section, the characters who see themselves as comparatively noble and clean-cut are forced to deal with the fact that they too are capable of more than they thought.