What is the connection of Egyptian mythology to Atlantis?
As writing an answer to my own question, I came across this,
Plutarch, Life of Solon 26. 1 (trans. Perrin) (Greek historian C1st - C2nd A.D.) :
"He [Solon] also spent some time in studies with Psenophis of Heliopolis [in Egypt] and Sonkhis (Sonchis) of Sais, who were very learned priests. From these, as Plato says, he heard the story of the lost Atlantis, and tried to introduce it in a poetical form to the Greeks."
What is the connection of the Greek and Egyptian myths about Atlantis?
If there ever was one, we don't know what it was. Most likely, there never was one.
The only real original source we have for the story of Atlantis is Plato. He used it as an allegory to help describe his vision of the best way to run things politically. It was sort of his equivalent of Thomas More's Utopia. The society itself appears to be very maritime (like Greece and decidedly unlike Egypt). It doesn't look at all like a myth an inland river-centered Egyptian would come up with.
All other sources we have for the story came after Plato, and seem to be based on his stories. So the most likely (and currently favored) supposition is that Plato himself made it up. Even if he didn't, he might as well have, because that's all we have.
It might actually be more accurate to say that Utopia was More's equivalent of Plato's Atlantis.
@T.E.D. - But wasn't Ancient Athens Plato's utopian state, and Atlantis it's militarily advanced adversary?
stories of sunken islands may well be in the realm of reality. Platos allegory of an advanced society may be embellished. This is of course difficult to separate, but reminiscent of flood myths. Flood of course does play a major role in Egyptian mythology. Metaphorical floods, e.g. invasions, might be appreciable, too, w.r.t. change-over, lost history and knowledge (language replacement), itself possibly caused by deluge.