[Madhatter]

Snails have a shell on their back, they still have a tail.
They don't like the sun, it dries their slime up that they use to get about. they produce the slime which acts as a lubricant and helps them stick to windows etc. They get about by rippling muscles along.
the longer tenticles are the 'eyes' the shorter are the 'nose' they breath through a small hole in it head, if you look close you'll see little white dots running around on a slug, so even little pets have little pets.
Snails were declining at one time, perhaps thats why you didn't see any rindy, but by what your saying they're increasing again.

hedgehogs also like worms, but they too are on the decline mainly because of an imported nasty worm that eats our english worms. Never get rid of garden worms, as well as a source of food for mr bristle the hedgehog, they make holes in the soil, which helps plants to grow better and helps the soil to drain better.