Semicassis genus of medium-sized predatory sea snails , marine gastropod molluscs in the subfamily Cassinae within the family Cassidae, the helmet snails and bonnet snails.
According to the World Register of Marine Species (WoRMS), the following species with valid names are included within the genus Semicassis :
Semicassis adcocki (Sowerby III, 1896) Semicassis angasi (Iredale, 1927) Semicassis bisulcata (Schubert & Wagner, 1829) Semicassis bondarevi Mühlhäusser & Parth, 1993 Semicassis bulla Habe, 1961 Semicassis canaliculata (Bruguière, 1792) Semicassis centiquadrata (Valenciennes, 1832) Semicassis cicatricosa (Gmelin, 1791) Semicassis craticulata (Euthyme, 1885) Semicassis faurotis (Jousseaume, 1888) Semicassis glabrata (Dunker, 1852) Semicassis granulata (Born, 1778) - synonym: Phalium granulatum (Born, 1778)Semicassis inornata (Pilsbry, 1895) Semicassis labiata (Perry, 1811) Semicassis microstoma (Martens, 1903) Semicassis paucirugis (Menke, 1843) Semicassis pyrum (Lamarck, 1822) Semicassis royana (Iredale, 1914) Semicassis saburon (Bruguière, 1792) Semicassis salmonea Beu, Bouchet & Tröndlé, 2012 Semicassis semigranosa (Lamarck, 1822) Semicassis sinuosa (Verco, 1904) Semicassis sophia (Brazier, 1872) Semicassis thachi Kreipl, Alf & Eggeling, 2006 Semicassis thomsoni (Brazier, 1875) Semicassis umbilicata (Pease, 1861) Semicassis westralis Kreipl, 1997 Semicassis whitworthi (Abbott, 1968) Species brought into synonymy Semicassis pauciruge : synonym of Semicassis paucirugis (Menke, 1843) Semicassis undulata (Gmelin, 1791) : synonym of Semicassis granulata undulata (Gmelin, 1791) Extinct species within this genus include:
Semicassis aldrichi Dall 1890 †Semicassis angasi Iredale 1927 †Semicassis deneseplicata Martin 1916 †Semicassis harpaeformis Lamarck 1803 †Semicassis labiata Perry 1811 †Semicassis monilifera Sowerby 1846 †Semicassis oligocalantica Vredenburg 1925 †Semicassis ovulum Ortmann 1900 †Semicassis pyshtensis Addicott 1976 †Semicassis reclusa Guppy 1873 †
Fossils of species within this genus have been found all over the world in sediments from Eocene to Quaternary (age range: 37.2 to 0.0 million years ago).
