Tidying up the Back 40 (inches) this time of year inevitably unearths some signs of life settling in for the winter. This is one of several very small disk snails I’ve found attached to brick or metal outside. I’ve seen these critters before and think they are probably Discus rotundatus, immigrants from Europe like many another Brooklynite.
They’re small, about 3/16ths inch across. As such, they present a photographic challenge. I bought one in to try another series of shots, and the snail itself emerged to see what the hell was going on.
This one was returned to the Back 40.
Aren’t those shells amazing?
Vocabulary builder: Estivation, or aestivation, a form of summer-time hibernation, from the Latin word for summer. In hot, dry seasons, some land snails will pull themselves into their shells and chill out for a while, awaiting the days of greater moisture. They seal their shells with a membrane of dried mucus, or a calcium carbonate-reinforced barrier called an epiphragm. For winter, they can also tuck in, close down, seal up, and nestle under some kind of shelter to survive the cold. Not so different, really, from some people I know….
Backyard and Beyond 
Gorgeous meditative spiral – love seeing the little head pop out. And yeah, I know what you mean abt estivatious people – except for the mucous plug, I hope.
I love these! I’ve never seen any like them before; out here, we mostly have grove snails.
For certain, this is Discus rotundatus.
Small snails are a challenge to photograph!
Thanks, Robert. I’m looking forward to seeing what the spring brings to the back yard again.