Shell medium-sized, flat to conical, thin, umbilicate, with radially arranged peripheral spines (in the genera Onustus or Stellaria), subsutural skirt-like extensions (Onustus, Xenophora) or, as in the genera Stellaria, Xenophora, with foreign objects cemented to the shell. « The mode of life of xenophorids is arranged around prevention of detection. The animal, when it extends from the shell, lives within the enclosed space between the shell base and the substrate, fenced by the attached objects or the flange in wide-flanged species. The animal moves its shell in jerks, by planting the foot in the substrate and lifting the shell forward by about half a base diameter. Feeding occurs within the protective cage, by consuming microscopic algae or forams with the proboscis. Faeces are buried in a hole dug with the snout, a procedure which no doubt assists with preventing detection. » – seashellsofnsw.org.au. Aperture large, flat.
 

This genus aggregates all the species that, at once, cement foreign matter around their periphery, and do not bear a skirt-like peripheral extension.