which reproduce the radial profiles of observed rotation velocity and velocity dispersion $c_{obs}$ of disk stars. Still, the estimation of disk masses for galaxies of different types presented in this paper allows to conclude that there is no significant systemic dynamical overheating of disks in most of galaxies, except lenticulars, where the velocity dispersion often exceeds the threshold needed for marginal stability. It follows that many spiral galaxies have not suffered a strong gravitation perturbations or mergings after the formation of bulk of their stars. This result creates a certain problem in the generally accepted theory of galaxies formation in a gravitational well of dark halo (see e.g. the discussion in Zasov, Silchenko, 2010). The conclusion of marginal stability of disks, however, may not concern their outermost regions, which require an individual analysis and often may be dynamically overheated.

It is essential, that the excessively high velocity dispersion at $R=2h$ usually takes place in galaxies which, if to judge by color indexes, have a weak star formation (color index $(B-V)_0 > 0.7$). Most of them belong to $S0/a-S0$ types. For these galaxies almost total absence of young stars and gas parallel with high stellar velocity dispersion apparently resulted from at 