For shell fish use a cream of chicken base rather than a white wine fish fumet base.
In a large pot, put chicken bones, bits of chicken, a veal shank (small), 4 chopped onions, 2 chopped carrots, 4 stalks of celery, and 4 quarts of chicken broth, and a little bit of water. Bring to boil.
Separately: Make roux of 8 tablespoons butter and 1 cup of flour. Stir in enough of soup to make a smooth consistency.
Add roux to soup and mix well with a whisk. Simmer for 3 hours very slowly, skimming occasionally to remove impurities. Strain and cool.
Now saute lightly 2 pounds of crab meat in 8 tablespoons butter. Add 1/2 cup brandy and flame. After flame goes down, add 2 cups dry white wine and a cup of clam juice.
Cook, covered, for 10 minutes. Strain reserving the liquid and crab meat separately. (If you use good lump crab it will remain in edible bits and may be added to soup (see below), if not discard.)
Add crab liquid to 2 quarts of chicken base and strain whole amount through cheese cloth. Bring to boil; reduce heat and keep warm. Just before serving, add crab meat, 6 tablespoons of heavy cream, 4 tablespoons of butter, and 4 tablespoons brandy.