  In the framework of seesaw mechanism with three neutrino flavors, we propose
tentatively an efficient parametrization for the spectra of Dirac and
righthanded Majorana neutrino mass matrices in terms of three free parameters.
Two of them are related to (and determined by) the corresponding parameters
introduced previously for the mass spectra of charged leptons and up and down
quarks. The third is determined from the experimental estimate of solar $\Delta
m^2_{21}$. Then, the atmospheric $\Delta m^2_{32}$ is {\it predicted} close to
its experimental estimation. With the use of these three parameters all light
active-neutrino masses $ m_1 < m_2 < m_3$ and heavy sterile-neutrino masses $
M_1 < M_2 < M_3$ are readily evaluated. The latter turn out much more {\it
hierarchical} than the former. The lightest heavy mass $ M_1$ comes out to be
of the order $O(10^6 {\rm GeV})$ so, it is too light to imply that the
mechanism of baryogenesis through thermal leptogenesis might work.
