  The Nucleon- and the Lambda-excitation spectrum exhibit parity doublets, i.e.
states of the same spin but with opposite parity being almost degenerate in
mass. It is shown that in a relativistic quark model with instantaneous
interaction kernels, where confinement is implemented by a linearly rising
potential and the major mass splittings are generated from an interaction based
on instanton effects, this degeneracy occurs quite naturally: Once the
parameters of the instanton induced interaction are fixed to reproduce the
ground state octet-decuplet splittings, some states are selectively lowered to
a position which is degenerate with states of opposite parity. Some observable
consequences are briefly discussed.
