  Consider the family S of irreducible plane curves of degree n with d nodes
and k cusps as singularities. Let W be an irreducible component of S. We
consider the natural rational map from W to the moduli space of curves of genus
g=(n-1)(n-2)/2-d-k. We define the "number of moduli of W" as the dimension of
the image of W with respect to this map. If W has the expected dimension equal
to 3n+g-1-k, then the number of moduli of W is at most equal to the min(3g-3,
3g-3+\rho-k), dove \rho is the Brill-Neother number of the linear series of
degree n and dimension 2 on a smooth curve of genus g. We say that W has the
expected number of moduli if the equality holds. In this paper we construct
examples of families of irreducible plane curves with nodes and cusps as
singularities having expected number of moduli and with non-positive
Brill-Noether number.
