In a bowl whisk together the butter, the eggs, the sour cream, the parsley, the lemon juice, the Worcestershire sauce, the paprika, the salt, and the cayenne and stir in the crab meat and the bread crumbs gently. Form 1/2-cup measures of the mixture into twelve 3/4-inch-thick cakes and transfer the crab cakes as they are formed to a baking sheet sprinkled with half the cornmeal. Sprinkle the crab cakes with the remaining cornmeal and chill them, covered with plastic wrap, for at least 1 hour or overnight.
In a large heavy skillet heat the oil over moderately high heat until it is hot but not smoking and in it sauté the crab cakes in batches, turning them once, for 3 to 4 minutes on each side, or until they are golden, transferring them as they are cooked to paper towels to drain. Keep the crab cakes warm on another baking sheet in a 200°F. oven. Serve the crab cakes with the tarragon tartar sauce and the lemon wedges.
Makes about 12 crab cakes, serving 6.