  The conductance through a quantum wire of cylindrical cross section and a
weak bulge is solved exactly for two electrons within the Landauer-Buettiker
formalism. We show that this 'open' quantum dot exhibits spin-dependent Coulomb
blockade resonances resulting in two anomalous structure on the rising edge to
the first conductance plateau, one near 0.25(2e^2/h), related to a singlet
resonance, and one near 0.7(2e^2/h), related to a triplet resonance. These
resonances are generic and robust, occurring for other types of quantum wire
and surviving to temperatures of a few degrees.
