  Using 29.1fb-1 of data accumulated at the Upsilon(4S) with the Belle detector
at KEKB, we have studied the decay modes B0bar->Lambda_c+ pbar pi+pi-, B- ->
Lambda_c+ pbar pi-, and B0bar ->Lambda_c+ pbar. We report branching fractions
of exclusive B decays to charmed baryons with four-, three- and two-body final
states, including intermediate Sigma_c++ and Sigma_c0 states. We observed B0bar
-> Sigma_c(2455)++pbar pi- for the first time with a branching fraction of
(2.38+0.63-0.55+-0.41+-0.62)x10-4 and observed evidence for the two-body decay
B- ->Sigma_c(2455)0 pbar with a branching fraction of
(0.45+0.26-0.19+-0.07+-0.12)x10-4. We also set improved upper limits for the
two-body decays B0bar -> Lambda_c+ pbar and B- -> Sigma_c(2520)0 pbar.
