Turtles in The Body?

[JSW]

I've just saved Li and gained the Spirit Form, however I'm afraid that I'm getting close to the end of the game and that if I travel further I'll reach a point of no return, which would be a problem since there's still a fair bit of non-essential stuff I'd like to do in the rest of the game before I complete it (find that third memory, for one.) If I use the downward passage to go deeper into The Body will I encounter an Ancient Turtle that will let me return to the earlier parts of the game, or should I turn back  now and swim to The Abyss under my own power?

[Zeke]

There is a turtle deeper on.  It's just before things start happening.  You'll know.

[Danger Mouse]

There's no point at which you can't turn back and do whatever you like. Probably one of the best things about the game.

[silverflagon]

There is a turtle deeper on.  It's just before things start happening.  You'll know.

And a save point also