  Associated to the classical Weyl groups, we introduce the notion of
degenerate spin affine Hecke algebras and affine Hecke-Clifford algebras. For
these algebras, we establish the PBW properties, formulate the intertwiners,
and describe the centers. We further develop connections of these algebras with
the usual degenerate (i.e. graded) affine Hecke algebras of Lusztig by
introducing a notion of degenerate covering affine Hecke algebras.
