  We discuss structure formation in cosmic string theories. Emphasis is laid on
the properties of the peculiar velocity field, non-gaussian features and
clusters of galaxies. It is found that the predicted peculiar velocity field is
quiet ($v<150$ km/s for $L>30 h^{-1}$ Mpc) for models with ($\Omega_0 h \leq
0.2$) which is in disagreement with the results from POTENT at large scales
($>30h^{-1}$ Mpc), consistent, however, with the analysis of the peculiar
velocity field of spiral galaxies by Giovannelli et al.. Using the
Press-Schechter formalism we calculate the abundances of X-ray clusters. It is
found that in CDM models a mass fluctuation $\sigma_8 = 0.6...0.7$ is needed
with $\Omega_0 h =0.1...0.2$ in order to explain the current data.
