Wronski algebra systems on families of singular curves

We replace the sheaves of principal parts on a family of reduced, local complete intersection curves by natural sheaves of algebras that are locally free. Our motivation is to be able to associate to any linear system on the family a Wronski system, as defined by Laksov and Thorup. By applying their general theory of Wronski systems, we obtain in particular a Weierstrass divisor on the family, in case there are no degenerate components on a general fibre.