# Cassis (gastropod)

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.

## Species

The genus Cassis includes extant and extinct species:
* Cassis abbotti Bouchet, 1988
* † Cassis altispira Beu 2010
* † Cassis birmanica Vredenburg 1921
* † Cassis brasili (Cossmann & Pissarro, 1905)
* † Cassis calusa Petuch and Berschauer 2018
* 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 lelongi Gain, Belliard & Le Renard, 2017
* † Cassis maccormacki Olsson 1928
* Cassis madagascariensis Lamarck, 1822
* † Cassis mammillaris Grateloup 1927
* Cassis nana Tenison-Woods, 1879
* † Cassis nigellensis Gain, Belliard & Le Renard, 2017
* Cassis norai Prati Musetti, 1995
* Cassis nummulitiphila Sacco 1890
* † Cassis parfouruorum Gain, Belliard & Le Renard, 2017
* Cassis patamakanthini Parth, 2000
* † Cassis powelli Petuch and Berschauer, 2018
* 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)