  We compare the statistical properties of structures normal and transverse to
the line of sight which appear in theoretical N-body simulations of structure
formation, and seem also to be present in observational data from redshift
surveys. We present a statistic which can quantify this effect in a
conceptually different way from standard analyses of distortions of the
power-spectrum or correlation function. From tests with $N$--body experiments,
we argue that this statistic represents a new and potentially powerful
diagnostic of the cosmological density parameter, $\Omega_0$.
