Mystery solved. I had a look at the original record for Narcisse Chouinard's first marriage. The bride's surname is Moquin, but the M is not very well formed, and overlaps with a letter from the line above, so it could conceivably be mis-read as a P. Very sloppy work on the part of the book's author.
Just in case, I add the details of Narcisse Sr's marriage:
Narcisse Chouinard (Francois, Marie Coache) married Emerante Moquin (Francois, Genevieve Monty) 07/07/1840 in Longueuil (Chambly county).