As a slug, Norman admires the patterned shells on snails’ backs. And who can blame him? In Hendra’s vivid illustrations, their shells are as bright and enticing as peppermint candies.

Let's start with the slugs. What gardener has not encountered these shell-less gastropods ... Those that are made of iron phosphate are the safe ones when it comes to children and pets.

During his time, an internal calcareous shell in the shape of a slightly bend, hollow cone grows inside of the body of these animals which remains after their death. Since also extant slugs ...

Were there shells? Does a gooey slug even fossilize? Turns out the answer is no, no, yes, as demonstrated by an incredible fossil slug that’s half a billion years old. The fossil is Shishania ...