Here is the saurian—this is serious! At all events, the decision he obviously has made means that it will be a situation touching his instincts, the very foundations of his being.
Jung uses 'saurian' as an interpretive exclamation to signal that the dreamer's situation has penetrated to the archaic-instinctual level, making the reptilian image a direct measure of psychic depth and existential gravity.
, Dream Analysis: Notes of the Seminar Given in 1928-1930, 1984thesis