Extended quote:
Dream is the personalized myth, myth the depersonalized dream; both myth and dream are symbolic in the same general way of the dynamic of the psyche. But in the dream the forms are quirked by the peculiar troubles of the dreamer, whereas in myth the problems and solutions shown are directly valid for all mankind.
I found this via Steven Aizenstat, who said in Dream Tending: "A myth is a story that expresses something meaningful about a culture, from origins to values to sanctioned social interactions. Every night the dreaming psyche is generating something of our own personal mythology, informing us about our origins, values, and so on."