  We have analyzed the observed radial-velocity curve for the X-ray binary M33
X-7 in a Roche model. We have analyzed the dependence between the component
masses and the degree of filling of the optical star's Roche lobe to obtain the
ratio of the masses of the optical star and compact object. For the most
probable mass of the optical star, $m_v=70M_{\odot}$, the mass of the compact
object is $m_x=15.55\pm3.20 M_{\odot}$. It has been shown that black holes with
masses of $m_x=15M_{\odot}$ and even higher can form in binaries. We present
characteristic evolutionary tracks for binary systems passing through an
evolutionary stage with properties similar to M33 X-7 - type objects. According
to population-synthesis analyses, such binaries should be present in galaxies
with masses of at least $10^{11}M_{\odot}$. The present number of such systems
in M33 should be of the order of unity. We have also studied the evolutionary
status of the X-ray binary IC 10 X-1 with a Wolf-Rayet component, which may
contain a massive black hole. The final stages of the evolution of the M33 X-7
and IC 10 X-1 systems should be accompanied by the radiation of gravitational
waves.
