Cassis, common name the helmet shells, is a genus of very large sea snails, marine gastropod mollusks in the family Cassidae, the helmet shells and their allies. This is the type genus of the subfamily Cassinae.
The genus Cassis includes 11 extant species and about 20 extinct species:
Cassis abbotti Bouchet, 1988
Cassis altispira Beu 2010†
Cassis birmanica Vredenburg 1921†
Cassis cornuta (Linnaeus, 1758)
Cassis costulifera Beu 2010†
Cassis delta Parker 1948†
Cassis depressior Martin 1879†
Cassis fimbriata Quoy & Gaimard, 1833
Cassis flammea Linnaeus, 1758
Cassis flintensis Mansfield 1940†
Cassis floridensis Tucker and Wilson 1932†
Cassis glaucoides Martin 1879†
Cassis herklotsi Martin 1879†
Cassis ketteri Parodiz and Tripp 1992†
Cassis kreipli Morrison, 2003
Cassis maccormacki Olsson 1928†
Cassis madagascariensis Lamarck, 1822
Cassis mammillaris Grateloup 1927†
Cassis nana Tenison-Woods, 1879
Cassis norai Prati Musetti, 1995
Cassis nummulitiphila Sacco 1890
Cassis patamakanthini Parth, 2000
Cassis retusa Michelotti 1861
Cassis subtuberosa Hanna 1926
Cassis sulcifera Sowerby 1850
Cassis tessellata Gmelin, 1791
Cassis togata White 1887
Cassis tuberosa Linnaeus, 1758
Cassis vialensis Fuchs 1870
Fossils of the sea snails within this genus have been found all over the world in sediments from Paleocene to Recent (age range: 66 to 0 million years ago).
Species brought into synonymy:
Cassis achatina Lamarck, 1816: synonym of Semicassis labiata (Perry, 1811)
Cassis areola (Linnaeus, 1758): synonym of Phalium areola (Linnaeus, 1758)
Cassis bituberculosa Martens, 1901: synonym of Echinophoria bituberculosa (Martens, 1901)
Cassis callosa Röding, 1798: synonym of Nassarius gibbulosus (Linnaeus, 1758)
Cassis centiquadrata (Valenciennes, 1832): synonym of Semicassis centiquadrata (Valenciennes, 1832)
Cassis cernica Sowerby III, 1888: synonym of Casmaria ponderosa ponderosa (Link, 1807)
Cassis coarctata G.B. Sowerby I, 1825: synonym of Cypraecassis coarctata (G.B. Sowerby I, 1825)
Cassis coronadoi Crosse, 1867: synonym of Echinophoria coronadoi (Crosse, 1867)
Cassis dalli Anderson, 1929: synonym of Echinophoria hadra (Woodring & Olsson, 1957)
Cassis glans Röding, 1798: synonym of Demoulia abbreviata (Gmelin, 1791)
Cassis glauca (Linnaeus, 1758): synonym of Phalium glaucum (Linnaeus, 1758)
Cassis globulus Menke, 1829: synonym of Demoulia ventricosa (Lamarck, 1816)
Cassis gracilenta Yokoyama, 1928: synonym of Cyllene gracilenta (Yokoyama, 1928)
Cassis japonica Reeve, 1848: synonym of Semicassis bisulcata (Schubert & Wagner, 1829)
Cassis labrosa Martini, 1773: synonym of Malea pomum (Linnaeus, 1758)
Cassis ringens Swainson, 1822: synonym of Malea ringens (Swainson, 1822)
Cassis rufa (Linnaeus, 1758): synonym of Cypraecassis rufa (Linnaeus, 1758)
Cassis spinosa (Gronovius, 1781): synonym of Cassis tessellata Gmelin, 1791
Cassis tenuis Wood, 1828: synonym of Cypraecassis tenuis (Wood, 1828)
Cassis vibex (Linnaeus, 1758): synonym of Casmaria erinaceus (Linnaeus, 1758)
Cassis wyvillei Watson, 1886: synonym of Echinophoria wyvillei (Watson, 1886)
