|Calyptraeidae, the slippersnails, have flattened, sometimes coiled shells with either a small spire or no spire. Their shells lack operculums (the hard plate at the opening of the apertures. These mollusks live inside a "shelf" on the underside of the shell and extend their foot out to attach to hard surfaces. They are mostly sedentary but are able to slowly creep along a surface. Their diet consists of small plankton which are filtered from the water. They may also be referred to as "slipper limpets" due to the resemblance of some shells to a limpet. There are 6 species reported from Texas.