Spiral snail hiding from the rain

I have read a great many things that talk about the importance of planning in photography, and I agree, to an extent. Just as important though, I think, is to just go for a wander.

I was on one such wander around the local reserve, when a fairly sharp shower sent me scurrying under a tree, and while I was there, I spotted this small snail – species unknown – on the underside of a near by leaf. I had my 300 mm zoom equipped already, so it was quite easy to isolate the snail, and by using a fairly fast aperture, f7 I think it was, I kept all of the leaf in focus while throwing the background out. The advantage of the zoom lenses for this type of tight shot is their very narrow depth of field, and I think it works really well here. Compositionally, the angle of the leaf gives a nice stable implied triangle, helping the image to feel balanced and harmonious, but not dull because the snail is off centre. Harmony is maintained though, by the out of focus yellow stem in the background, the weight of its colour balanced by the lack of focus. I’m really happy with this one.

Anyone know what the species of snail is?