In a large plastic bag, mix the flour, cornmeal, salt and pepper. Add half the smelt, close the bag securely, and shake well to coat the fish with the flour mixture.
Heat 2 tablespoons of the oil in a large skillet over medium-high heat. Add the coated smelt, with out crowding, and fry 3 to 4 minutes, turning once, until the cooked fish are golden brown and opaque throughout (cut into one to check for doneness). Place the smelt on a baking sheet and keep warm in the oven.
Repeat the procedure with the remaining flour mixture, smelt, and 2 tablespoons canola oil. When all the smelt are cooked, decrease the heat to medium, squeeze 4 of the lemon wedges into the oil remaining in the pan, and scrape up any cooked bits of fish or batter left in the skillet. Add butter and cook until melted, stirring well.
Divide the smelt among individual plates and drizzle the lemon butter over the fish. Serve immediately, garnishing the fish with remaining lemon wedges.