  We obtained 500-second F606W WFPC2 images of 256 of the nearest (z<0.035)
Seyfert 1,Seyfert 2, and starburst galaxies. Less than 10% show tidal features
or multiple nuclei. The incidence of inner starburst rings is about 10% in both
classes of Sy galaxies. In contrast, galaxies with H II region emission line
spectra appear substantially more irregular because of their much higher
specific rates of star formation. An unresolved central continuum source in our
HST images is a virtually perfect indicator of a Sy1 spectrum. 52% of these Sy1
point sources are saturated in our images; we use their wings to estimate their
magnitudes. The converse is not however true, as over a third of Sy's with
direct spectroscopic evidence for broad Balmer wings show no nuclear point
source. Like the Sy2's, they have central surface brightnesses consistent with
those expected for the bulges of normal galaxies. The frequency of bars in
Sy1's and 2's and non-Sys are the same. The Sy2 galaxies are significantly more
likely to show nuclear dust absorption, especially in lanes and patches which
are irregular or reach close to the nucleus. The difference cannot be explained
by different average redshifts or selection techniques. This is confirmed by
our morphology classifications, which show that Sy1 nuclei reside in earlier
type galaxies than Sy2 nuclei. This intrinsic difference in host galaxy
properties may undermine the strong unification hypothesis for Sy galaxies that
they appear different due to the orientation of their central engine. The
excess galactic dust we see in Sy2's may cause substantial absorption which
obscures their hypothesized broad emission-line regions and central nonstellar
continua. This galactic dust could produce much of the absorption in Sy2 nuclei
which had instead been attributed to a thick dusty accretion torus.
