  The cosmic string scenario in an open universe is developed -- including the
equations of motion, a model of network evolution, the large angular scale CMB
temperature anisotropy, and the power spectrum of density fluctuations produced
by cosmic strings with dark matter. First we derive the equations of motion for
cosmic string in an open FRW space-time and construct a quantitative model of
the evolution of the gross features of a cosmic string network. Second, we
apply this model of network evolution to estimate the rms CMB temperature
anisotropy induced by cosmic strings, obtaining the normalization for the mass
per unit length $\mu$ as a function of $\Omega$. Third, we consider the effects
of the network evolution and normalization in an open universe on the large
scale structure formation scenarios with either cold or hot dark matter.
