  A nonstandard system of differential equations describing two-species phase
segregation is considered. This system naturally arises in the asymptotic
analysis recently done by Colli, Gilardi, Krejci and Sprekels as the diffusion
coefficient in the equation governing the evolution of the order parameter
tends to zero. In particular, a well-posedness result is proved for the limit
system. This paper deals with the above limit problem in a less general but
still very significant framework and provides a very simple proof of further
regularity for the solution. As a byproduct, a simple uniqueness proof is given
as well.
