Typhon/exultants not Of This Urth?

Someone (apologies - I forget who) mentioned on the Whorl list that there was evidence that Typhon was of extraterrestrial origin and probably brought the exultants with him. I fairly recently re-read BOTNS and - although I will freely admit to being the most attentive of Wolfe readers - I'm not sure where this is implied. Can someone quote chapter and verse? Thanks, Dave W/newt P.S. I'm eagerly awaiting the promised illumination of the Jonas/Miles/Hethor/whoever mystery, which I find both fascinating and baffling. Not to mention the exact nature of "poor" Valeria and the Atrium of Time, which I am still puzzled by after three readings...