Another weeny snail from the limestone at Chillagoe. This is a pupillid with close relatives in SE Asia. It has a discontinuous distribution in Australia — it occurs on widely-spaced limestone outcrops in tropical Queensland, the Northern Territory and NW Western Australia.
It's an odd-looking animal. The shell aperture is expanded like the bell of a tuba. It seals onto rock faces to prevent desiccation during the dry season. Although they are abundant in suitable habitats, their small size and drab coloration make them very difficult to spot in situ.
(Thanks to M for the top photograph.)