Prepare the Rice: Cook the long grain and wild rice according to the package instructions. Preheat your oven to 375°F (190°C).

Mix Ingredients: In a large bowl, combine the crabmeat, shrimp, celery, onion, green pepper, mushrooms, and pimientos.

Create the Sauce: Whisk together mayonnaise, milk, pepper, and Worcestershire sauce until smooth.

Combine Ingredients: Fold the sauce into the seafood mixture, then add the cooked rice and mix gently.

Transfer and Top: Pour the mixture into a greased 13x9-inch baking dish and top with breadcrumbs.

Bake: Place in the oven and bake for 40-50 minutes until bubbly and golden brown.