2a the ratio of radial velocity dispersion to circular velocity $c_r/V_c$ is correlated with morphological type of galaxies. Type $t$ is coded as de Vaucouleurs numerical type: spiral galaxies correspond to the interval $t$=1 ($Sa$) — 7 ($Sd$), higher values of $t$ represent irregular galaxies, and $t=-1...-3$ are related to S0 galaxies. The correlation between $c_r/V_c$ and type is rather weak, moreover, if to exclude S0 galaxies, it almost disappears. The same conclusion may be done for the correlation between $c_r$ and $V_c$ at the fixed radius $R=2h$ (Fig. 2b). It means that it is impossible to get a reliable estimation of disk velocity dispersion by the indirect way, from the type of a galaxy or its rotation velocity, as it was for example suggested by Bottema (1993).

The conclusion that most of the galaxies with dynamically overheated disks are among the red galaxies (Fig. 1a) is confirmed by Fig. 3, where color index is compared with the relative disk mass $M_d/M_t$ within the optical radius $R=4h$. As above, here $M_d$ corresponds to disks, which are assumed to be marginally stable at least at $R=2h$, and total mass of a galaxy was calculated as $M_t = 4h\cdot V_c^2/G$. [^2]

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