Distribution: Abundantly common throughout the Solitary Islands Marine Park. Endemic to the east coast of Australia, occurs between southern Queensland and southern New South Wales.

Ecological Notes: Common on inshore rocky reef areas, exposed positions, lower intertidal to shallow subtidal, depths to 15 m.

Additional Notes: Shell height less than width, in the ratio 0.75 to 0.9. Shell white, grey, fawn or reddish brown, often covered with algal growths, interior nacreous. Operculum white with purple or blue areas. Herbivorous, feeding on macro algae. Grows to about 7 cm tall.

References: Atlas of Living Australia website at https://bie.ala.org.au/search?q=astralium+tentoriiforme. Accessed 15/12/2019.

The Seashells of New South Wales, Des Beechey, Senior Fellow, Australian Museum, Release 25. Website at http://seashellsofnsw.org.au/Turbinidae/Pages/Astralium_tentoriiformis.htm Accessed 15/12/2019.