  The generalized Stieltjes--Wigert polynomials depending on parameters 0\le
p<1 and 0<q<1 are discussed. By removing the mass at zero of the N-extremal
solution concentrated in the zeros of the D-function from the Nevanlinna
parametrization, we obtain a discrete measure \mu^M which is uniquely
determined by its moments. We calculate the coefficients of the corresponding
orthonormal polynomials (P^M_n). As noticed by Chihara, these polynomials are
the shell polynomials corresponding to the maximal parameter sequence for a
certain chain sequence. We also find the minimal parameter sequence, as well as
the parameter sequence corresponding to the generalized Stieltjes--Wigert
polynomials, and compute the value of related continued fractions. The mass
points of \mu^M have been studied in recent papers of Hayman, Ismail--Zhang and
Huber. In the special case of p=q, the maximal parameter sequence is constant
and the determination of \mu^M and (P^M_n) gives an answer to a question posed
by Chihara in 2001
