  Cabibbo-allowed nonleptonic weak decays of charmed baryons
$\lamc,~\xin,~\xip$ and $\Omega_c^0$ into an octet baryon and a pseudoscalar
meson are analyzed. The nonfactorizable contributions are evaluated under pole
approximation, and it turns out that the $s$-wave amplitudes are dominated by
the low-lying $\halfm$ resonances, while $p$-wave ones governed by the
ground-state $\halfp$ poles. The MIT bag model is employed to calculate the
coupling constants, form factors and baryon matrix elements. Our conclusions
are: (i) $s$ waves are no longer dominated by commutator terms; the
current-algebra method is certainly not applicable to parity-violating
amplitudes, (ii) nonfactorizable $W$ exchange effects are generally important;
they can be comparable to and somtimes even dominate over factorizable
contributions, depending on the decay modes under consideration, (iii)
large-$N_c$ approximation for factorizable amplitudes also works in the heavy
baryon sector and it accounts for the color nonsuppression of $\lamc\ri
p\bar{K}^0$ relative to $\lamc\ri\Lambda\pi^+$, (iv) a measurement of the decay
rate and the sign of the $\alpha$ asymmetry parameter of certain proposed decay
modes will help discern various models; especially the sign of $\alpha$ in
$\lamc\ri\Sigma\pi$ decays can be used to unambiguously differentiate recent
theoretical schemes from current algebra, and (v) $p$ waves are the dominant
contributions to the decays $\lamc\ri\Xi^0 K^+$ and $\xin\ri\Sigma^+ K^-$, but
they are subject to a large cancellation; this renders present theoretical
predictions on these two channels unreliable.
