At birth, the visceral hump turns along its lineal axis, eventually creating a coiled snail shell. Young snails have shells that are nearly transparent. The older they get, the thicker their shells become. Glands that are distributed across their body solidify the shell with calcium carbonate.

How is a shell formed?

As mollusks develop in the sea, their mantle tissue absorbs salt and chemicals. They secrete calcium carbonate, which hardens on the outside of their bodies, creating a hard shell. ... When a mollusk dies it discards its shell, which eventually washes up on the shore. This is how seashells end up on the beach.

Are snails born with a shell?

After a few weeks, the eggs hatch and the tiny baby snails emerge - already with their shells! ... The baby snail eats the egg from which it hatched because the egg contains calcium which helps its shell to harden. Over the coming months, as the snail grows, the shell will grow with it.