  The $1/N_c$ expansion method for studying the mass spectrum of excited
baryons is shortly reviewed together with applications to mixed symmetric
states. The $[{\bf 70, \ell^+}]$ multiplet, belonging to the $N$ = 2 band, is
reanalyzed, with emphasis on hyperons and the SU(3) symmetry breaking operators
entering the mass formula to first order. An important result is that the
hierarchy of masses as a function of strangeness is correctly reproduced for
all multiplets. Predictions for unknown excited hyperons to SU(6) $\times$ O(3)
multiplets are made.
