Despite its incorrect formation (the correct one would be Cassididae, based on the genitive form of Cassis), the ICZN has placed the name Cassidae Latreille, 1825 on the official list of family names, therefore avoiding homonymy with Cassididae Stephens, 1831 (based on Cassida Linnaeus, 1758, a chrysomelid beetle); Opinion 1023 (1974, Bulletin of Zoological Nomenclature 31: 127–129).

[1] Species of this family occur in tropical and temperate seas from the intertidal zone to depths of 100 m (330 ft), buried in the sand during the day and becoming active at night.

The shells are large, thick, subglobular with dextrally coiled, sometimes varicose, whorls, and a short spire.

The snail then makes a hole in the urchin through the combined action of a secretion which is rich in sulfuric acid and by rasping with their radula.

[2] In their taxonomy of the Gastropoda of 2005 Bouchet & Rocroi still listed Cassidae as Cassinae Latreille, 1825, a subfamily of Tonnidae Suter, 1913 (1825), following in this Riedel (1995).