Electron effective-mass values obtained from room-temperature magneto-Seebeck and Hall measurements on Cd3As2 have been gathered from the literature. Using Kane's model for an α-Sn-type inverted electronic energy band structure, the dispersion related for the conduction band has been obtained along with a Γ8-Γ6 energy gap of 0.19 eV. Combining these results with the available room-temperature optical data, the relative positions of other bands have been obtained. The heavy-hole valence band, whose maximum is displaced from Γ by ~ 10% of the distance to the Brillouin-zone edge, has a possible small overlap with the conduction band. These two Γ8 bands are split at Γ by a residual gap of ~ 0.04 eV. There is a second conduction band whose minimum at Γ is ~ 0.6 eV above the Γ8 valence band and perhaps a third one ~ 0.4 eV above the latter.