  Quark and pole models of nonleptonic decays of charmed baryons are analysed
from the point of view of their symmetry properties. The symmetry structure of
the parity conserving amplitudes that corresponds to the contribution of the
ground-state intermediate baryons is shown to differ from the one hitherto
employed in the symmetry approach. It is pointed out that the "subtraction" of
sea quark effects in hyperon decays leads to an estimate of $W$-exchange
contributions in charmed baryon decays that is significantly smaller than
naively expected on the basis of $SU(4)$. An $SU(2)_{W}$ constraint questioning
the reliability of the factorization technique is exhibited. Finally, a
successful fit to the available data is presented.
