I spotted a snail moving up the patio window after a rain shower so I took the opportunity to photograph it from beneath. This shows the mouth parts and two pairs of tentacles. The bigger, out of focus ones on top bear the eyes, and the ones at the bottom are just for feeling the way. If you look at the foot against the glass you can just see the undulating waves of movement running up along the sides.
As with most things, there are hidden fascinations waiting to be discovered, and I recommend this diagram of the anatomy of a snail, as well as this detailed discourse on the tentacles and eyes of snails.