![](http://upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Snail_diagram-en_edit1.svg/400px-Snail_diagram-en_edit1.svg.png)
A representation of the external and internal anatomy of a common air-breathing land snail such as Helix aspersa. Air-breathing land snails have a well-defined head with two or four sensory tentacles with eyes at the tips of the upper pair, a ventral foot, and a shell. The viscera are grouped in a hump that is contained within the spiral shell.