Circulus is a genus of very small and minute sea snails with an operculum, marine gastropod mollusks in the family Tornidae.
According to the World Register of Marine Species (WoRMS), the following species with valid names are included within the genus Circulus
Circulus biporcatus (A. Adams, 1863)
Circulus choshiensis (Habe, 1961)
Circulus cinguliferus (A. Adams, 1850)
Circulus congoensis (Thiele, 1925)
Circulus cosmius Bartsch, 1907
Circulus delectabile (Tate, 1899)
Circulus deprinsi Rolán & Swinnen, 2013
Circulus harriettae (Petterd, 1884)
Circulus liratus (A. E. Verrill, 1882)
Circulus liricincta (Garrett, 1873)
Circulus marchei (Jousseaume, 1872)
Circulus microsculpturatus Oliver & Rolán, 2011
Circulus modestus (Gould, 1859)
Circulus orbignyi (P. Fischer, 1857)
Circulus pseudopraecedens Adam & Knudsen, 1969
Circulus rossellinus Dall, 1919
Circulus ryalli Oliver & Rolán, 2011
Circulus semisculptus (Olsson & McGinty, 1958)
Circulus senegalensis Adam & Knudsen, 1969
Circulus smithi Bush, 1897
Circulus soyoae (Habe, 1961)
Circulus stephani Rolán & Ryall, 2002
Circulus striatus (Philippi, 1836)
Circulus supranitidus (Wood S., 1848)
Circulus teramachii (Habe, 1958)
Circulus texanus (Moore, 1965)
Circulus tornatus (A. Adams, 1864)
The Indo-Pacific Molluscan Database also mentions the following species with names in current use :
Circulus acutilirata (Thiele, 1925)
Circulus aequatorialis (Thiele, 1925)
Circulus angulata (Adams)
Circulus callusa (Laseron, 1958)
Circulus duplicatus (Lischke, 1872)
Circulus gyalum (Melvill, 1904)
Circulus octolirata (P. Carpenter, 1856)
Circulus pachyston (Verco, 1907)
Circulus planorbis (Laseron, 1958)
Circulus sculptilis (Garrett, 1873)
Circulus transculpta (Laseron, 1958)
Circulus venusta (Hedley, 1901)
Circulus virginiae (Jousseaume, 1872)
Species brought into synonymy
Circulus biporcata [sic]: synonym of Circulus biporcatus (A. Adams, 1863)
Circulus carinulatus Locard, 1889: synonym of Circulus striatus (Philippi, 1836)
Circulus costulatus Locard, 1889: synonym of Circulus striatus (Philippi, 1836)
Circulus cubanus Pilsbry & Aguayo, 1933: synonym of Cyclostremiscus cubanus (Pilsbry & Aguayo, 1933)
Circulus dalli Bush, 1897: synonym of Cyclostremiscus dalli (Bush, 1897)
Circulus formosissimus Brugnone, 1873: synonym of Skeneoides jeffreysii (Monterosato, 1872)
Circulus hendersoni (Dall, 1927): synonym of Cyclostremiscus hendersoni (Dall, 1927)
Circulus jeffreysii Monterosato, 1872: synonym of Skeneoides jeffreysii (Monterosato, 1872)
Circulus margaritiformis (Dall, 1927): synonym of Cirsonella margaritiformis (Dall, 1927)
Circulus modesta [sic]: synonym of Circulus modestus (Gould, 1859)
Circulus stirophorus M. Smith, 1937: synonym of Cyclostremiscus beauii (P. Fischer, 1857)
Circulus tatei (Angas, 1878): synonym of Elachorbis tatei (Angas, 1878)
Circulus tornata [sic]: synonym of Circulus tornatus (A. Adams, 1864)
Circulus translucens (Dall, 1927): synonym of Xyloskenea translucens (Dall, 1927)
Circulus tricarinatus (Wood S., 1848): synonym of accepted as Circulus striatus (Philippi, 1836)
