The mudflat snail is different to all the other marine gastropods, it is a pulmonate, which means it has a rudimentary lung and no gills. When the tide is out air is pulled into the lung and the operculum is closed and the animal buries in the mud to wait for low tide. The shell is brown to khaki with a purple edge to the aperture.

It is abundant on mudflats where it is a deposit feeder, sifting through mud for organic material, such as microscopic algae and bacteria; it leaves a continuous faecal trail behind it.

Deposit feeder sifting through mud for organic matter.

It makes a nest of mud, mucous and eggs which hatch into free-swimming larvae. Active at low tide.
A traditional food of the Maori people

NZ Coastal Marine Invertebrates; Vol 1