  A new mechanism describing the formation of protogalaxies is proposed, which
is based on the second- order phase transition in the inflation stage and the
domain wall formation upon the end of inflation. The presence of closed domain
walls with the size markedly exceeding the cosmological horizon at the instant
of their formation and the wall collapse in the postinflation epoch (when the
wall size becomes comparable with the cosmological horizon), which leads to the
formation of massive black hole clusters that can serve as nuclei for the
future galaxies. The black hole mass distributions obtained do not contradict
the available experimental data. The number of black holes with M ~ 100 solar
masses ($M_{\odot}$) and above is comparable with the number of Galaxies in the
visible Universe. Development of the proposed approach gives ground for a
principally new scenario of the galaxy formation in the model of hot Universe.
