Using data collected by the CLEO detector in the $\ensuremath{\Upsilon}(4S)$ region, we report new measurements of the exclusive decays of B mesons into final states of the type ${\ensuremath{\Lambda}}_{c}^{+}\overline{p}n(\ensuremath{\pi}),$ where $n=0,1,2,3.$ We find signals in modes with one, two and three pions and an upper limit for the two-body decay ${\ensuremath{\Lambda}}_{c}^{+}\overline{p}.$ We also make the first measurements of exclusive decays of B mesons to ${\ensuremath{\Sigma}}_{c}\overline{p}n(\ensuremath{\pi}),$ where $n=0,1,2.$ We find signals in modes with one and two pions and an upper limit for the two-body decay ${\ensuremath{\Sigma}}_{c}\overline{p}.$ Measurements of these modes shed light on the mechanisms involved in B decays to baryons.