Moby-Dick Questions Chs. 33-34: Why do chapters 33 and 34 follow immediately

Why do chapters 33 and 34 follow immediately after the cetology chapter?  What is Ishmael classifying?  How do the mates proceed to supper and how do they disengage?  Why is Flask “a butterless man” (p. 163 [129]) and why does he always go hungry?  Compare the meal of the mates with the “almost frantic democracy” of the harpooners.