I’ll jump in on that, Mike, as I happen to have the reference at hand.
In the 3rd revised edition of the Hero with a Thousand Faces (© 2008 JCF, published by New World Library), it’s near the end of “The Road of Trials” section of the Initiation chapter, p. 89.
In the Princeton 2nd edition (which is text on the shelves of people who secured a copy between 1968 and 2008), it’s on p. 108.