We have analysed the distribution of inclination-corrected galaxy
concentrations in the Sloan Digital Sky Survey. We find that unlike most galaxy
properties, which are distributed bimodally, the distribution of concentrations
is trimodal: it exhibits three distinct peaks. The newly-discovered
intermediate peak, which consists of early-type spirals and lenticulars, may
contain ~60% of the number density and ~50% of the luminosity density of M_r <
-17 galaxies in the local universe. These galaxies are generally red and
quiescent, although the distribution contains a tail of blue star-forming
galaxies and also shows evidence of dust. The intermediate-type galaxies have
higher apparent ellipticities than either disc or elliptical galaxies, most
likely because some of the face-on intermediate types are misidentified as
ellipticals. Their physical half-light radii are smaller than the radii of
either the disc or elliptical galaxies, which may be evidence that they form
from disc fading. The existence of a distinct peak in parameter space
associated with early-type spiral galaxies and lenticulars implies that they
have a distinct formation mechanism and are not simply the smooth transition
between disc-dominated and spheroid-dominated galaxies.