  The spectra of disc accreting neutron stars generally show complex curvature,
and individual components from the disc, boundary layer and neutron star
surface cannot be uniquely identified. Here we show that much of the confusion
over the spectral form derives from inadequate approximations for
comptonization and for the iron line. There is an intrinsic low energy cutoff
in comptonised spectra at the seed photon energy. It is very important to model
this correctly in neutron star systems as these have expected seed photon
temperatures (from either the neutron star surface, inner disc or self-absorbed
cyclotron) of ~1 keV, clearly within the observed X-ray energy band. There is
also reflected continuum emission which must accompany the observed iron line,
which distorts the higher energy spectrum. We illustrate these points by a
reanalysis of the GINGA spectra of Cyg X-2 at all points along its Z track, and
show that the spectrum can be well fit by models in which the low energy
spectrum is dominated by the disc, while the higher energy spectrum is
dominated by comptonised emission from the boundary layer, together with its
reflected spectrum from a relativistically smeared, ionised disc.
