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As part of the HI Arecibo Galaxy Environments Survey (AGES) we have observed5$\times$4 degrees of sky centred on M33, reaching a limiting column density of$\sim 1.5 \times 10^{17}$ cm$^{-2}$ (line width of 10 km s$^{-1}$ andresolution 3.5\arcmin). We particularly investigate the absence of opticallydetected dwarf galaxies around M33, something that is contrary to galaxyformation models. We identify 22 discrete HI clouds, 11 of which are newdetections. The number of objects detected and their internal velocitydispersion distribution is consistent with expectations from standard galaxyformation models. However, the issue remains open as to whether the observedvelocity dispersions can be used as a measure of the HI clouds total mass i.e.are the velocities indicative of virialised structures or have they beeninfluenced by tidal interactions with other structures in the Local Group? Weidentify one particularly interesting HI cloud, AGESM33-31, that has many ofthe characteristics of HI distributed in the disc of a galaxy, yet there is noknown optical counterpart associated with it. This object has a total HI massof $1.22 \times 10^{7}$ M$_{\odot}$ and a diameter of 18 kpc if at the distanceof M33 ($D_{M33}=840$ kpc). However, we also find that there are numerous otherHI clouds in this region of sky that have very similar velocities and so it isplausible that all these clouds are actually associated with debris from theMagellanic stream.

The Arecibo Galaxy Environment Survey X: The Structure of Halo Gas Around M33