  The nature of Compact Groups (CGs) is investigated by comparing the
luminosities and morphologies of CG galaxies, CG Neighbours and Isolated
galaxies. CGs turn out to include more early type galaxies than Isolated
galaxies and fewer low-luminosity galaxies. The 33 CGs with a dominant E/S0 and
the 30 CGs with a dominant spiral have similar LF parameters. Spiral dominated
CGs have fewer galaxies at high and low luminosity in comparison with their
Neighbours, while E-S0 dominated CGs seem to lack only faint galaxies when
compared to their Neighbours. Ellipticals which are the dominant galaxy of a CG
are also brighter than all their Neighbours, while this holds true for only
half of the dominant spirals and S0s. Relations linking the number of
Neighbours of dominant E-S0s to the luminosity of E-S0s and to the difference
between the first and the second ranked CG members do suggest a link between
the formation of bright early-type galaxies and the presence of a group-like
potential. No similar relations are found for dominant spirals. These tentative
results are compatible with the assumption that CG dominant Ellipticals are
anomalous galaxies whose formation might have been a secondary outcome during
the process of groups formation.
