  In our quest to constrain the dynamical and structural properties of Local
Group spirals from high-quality interferometric data, we have performed a
neutral hydrogen survey in the direction of Messier 33. Here we present a few
preliminary results from the survey and show the benefits of fitting the HI
spectra by multiple peaks on constraining the structure of the Messier 33 disk.
In particular we report on the discovery of new inner spiral-like and outer
annular structures overlaying with the well-known main HI disk of Messier 33.
Possible origins of the additional outer annular structure are presented.
