  The masses of the yet undiscovered baryons containing single $c$ or $b$
quarks are estimated from the known masses using the following rules: equal
distances in mass between the isomultiplets forming sextets, equal mass
differences between the corresponding spin one-half baryons containing $c$ and
$b$ quarks, hyperfine splittings inversely proportional to the masses of the
heavy quarks.
