Shell growth
As the snail grows, so does its calcium carbonate shell. The shell grows additively, by the addition of new calcium carbonate, which is secreted by glands located in the snail's mantle.
Do snails come out of their shells?
Q: Can snails outgrow or leave their shells? A: No. The shell is present from the snail's early development, is attached to the snail, and grows along with the snail in a spiral shape. A snail can't crawl out of its shell any easier than you can walk away from your fingernails!
Do snails find shells or grow them?
As the snail continues to grow, its shell grows with it. The snail produces new shell material, like the soft material of its protoconch, that expands its shell and then hardens.
