Snails are born with rudimentary shells. On land snails, this embryonic shell can be seen even in the adult snail. The top of the shell [about one and a half whorls] is called the Protoconch and this has a different pattern from the rest of the shell. It is often used to help identify species of snail.
The protoconch is easily visible even on this tiny pinwheel snail from eastern Australia
Facts About Snails 
I like and thought this blog was interesting because it show the beauty ang rarity of each and every snail as well as giving it a story worth a thousand words. 🙂
This is very interesting work, the patterns are very pretty.
I found it interesting snails were born with shells
It s cool how the pattern changes at the top