  In response to criticism by Momany et al. (2004), that the
recently-identified Canis Major (CMa) overdensity could be simply explained by
the Galactic warp, we present proof of the existence of a stellar population in
the direction of CMa that cannot be explained by known Galactic components. By
analyzing the radial distribution of counts of M-giant stars in this direction,
we show that the Momany et al. (2004) warp model overestimates the number of
stars in the Northern hemisphere, hence hiding the CMa feature in the South.
The use of a better model of the warp has little influence on the morphology of
the overdensity and clearly displays an excess of stars grouped at a distance
of D=7.2\pm 0.3 kpc. To lend further support to the existence of a population
that does not belong to the Galactic disc, we present radial velocities of
M-giant stars in the centre of the CMa structure that were obtained with the
2dF spectrograph at the AAT. The extra population shows a radial velocity of
vr=109\pm4 km/s, which is significantly higher than the typical velocity of the
disc at the distance of CMa. This population also has a low dispersion (13\pm4
km/s). The Canis Major overdensity is therefore highly unlikely to be due to
the Galactic warp, adding weight to the hypothesis that we are observing a
disrupting dwarf galaxy or its remnants. This leads to questions on what part
of CMa was previously identified as the Warp and how to possibly disentangle
the two structures.
