  We have constructed a morphologically divided redshift distribution of faint
field galaxies using a statistically unbiased sample of 196 galaxies brighter
than I = 21.5 for which detailed morphological information (from the Hubble
Space Telescope) as well as ground-based spectroscopic redshifts are available.
Galaxies are classified into 3 rough morphological types according to their
visual appearance (E/S0s, Spirals, Sdm/dE/Irr/Pec's), and redshift
distributions are constructed for each type. The most striking feature is the
abundance of low to moderate redshift Sdm/dE/Irr/Pec's at I < 19.5. This
confirms that the faint end slope of the luminosity function (LF) is steep
(alpha < -1.4) for these objects. We also find that Sdm/dE/Irr/Pec's are fairly
abundant at moderate redshifts, and this can be explained by strong luminosity
evolution. However, the normalization factor (or the number density) of the LF
of Sdm/dE/Irr/Pec's is not much higher than that of the local LF of
Sdm/dE/Irr/Pec's. Furthermore, as we go to fainter magnitudes, the abundance of
moderate to high redshift Irr/Pec's increases considerably. This cannot be
explained by strong luminosity evolution of the dwarf galaxy populations alone:
these Irr/Pec's are probably the progenitors of present day ellipticals and
spiral galaxies which are undergoing rapid star formation or merging with their
neighbors. On the other hand, the redshift distributions of E/S0s and spirals
are fairly consistent those expected from passive luminosity evolution, and are
only in slight disagreement with the non-evolving model.
