  Let A be an association scheme on q\geq 3 vertices. We show that the
Bose-Mesner algebra of the generalized Hamming scheme H(n,A), for n\geq 2, is
not the Nomura algebra of a type II matrix. This result gives examples of
formally self-dual Bose-Mesner algebras that are not the Nomura algebras of
type II matrices.
