Capture 18 snails. Place them in a ventilated box with corn meal. With a sprayer bottle, spray the corn meal. Keep them in this environment at least 72 hours. Remove the snails and wash them in cold water. Drop them into boiling water with bay leaf and let simmer 15 minutes. Drain in colander and pick meat out of shell. Remove the fall or the tail end where the snail is attached to the shell. Wash snails in cold running water. Set aside. If you prefer, use canned snails, and rinse in cold water.
In a sauce pan, combine white wine, onion, garlic, allspice, soy sauce and vegetable seasoning. Add snails and cook over low heat 10 minutes. Remove and drain snails, reserving liquid. To this liquid add butter, parsley and green onions. Heat through; add nutmeg. Place mushroom caps in baking dish, top each with a snail, and pour liquid over all; bake at 450 degrees for 7 minutes. Serve immediately with sliced french bread.