Melt butter in large skillet. Saute shallots and scallions until soft. Add Worcestershire sauce, basil, salt & pepper.

Add shrimp and crab meat. Stir until shrimp are pink.

Add sour cream, heavy cream, Parmesan cheese, and heat thoroughly; do not boil.

Fold the sauce into the fettuccini, which has been boiled to al dente in salted water, and drained.

Sprinkle with parsley and Parmesan cheese.