Circulus is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of very small and minute sea snail

Sea snail

Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....

s with an operculum

Operculum (gastropod)

The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...

, marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 gastropod mollusks in the family Tornidae

Tornidae

Tornidae is a family of very small and minute sea snails with an operculum, marine gastropod mollusks in the clade Littorinimorpha. This family used to be known as the Vitrinellidae.-General characteristics:...

.

Species

According to the World Register of Marine Species

World Register of Marine Species

The World Register of Marine Species is a database that hopes to provide an authoritative and comprehensive list of names of marine organisms. The content of the registry is edited and maintained by scientific specialists on each group of organism. These taxonomists control the quality of the...

 (WoRMS), the following species with valid names are included within the genus Circulus

• Circulus congoensis (Thiele, 1925)
• Circulus hendersoni (Dall, 1927)
• Circulus liratus (A. E. Verrill, 1882)
• Circulus margaritiformis (Dall, 1927)
• Circulus microsculpturatus Oliver & Rolán, 2011
• Circulus pseudopraecedens Adam & Knudsen, 1969
• Circulus ryalli Oliver & Rolán, 2011
• Circulus semisculptus (Olsson & McGinty, 1958)
• Circulus senegalensis Adam & Knudsen, 1969
• Circulus smithi Bush, 1897
• Circulus stephani Rolán & Ryall, 2002
• Circulus striatus (Philippi, 1836)
• Circulus supranitidus (Wood S., 1848)
• Circulus texanus (Moore, 1965)
• Circulus translucens (Dall, 1927)

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 cingulifera A. Adams, 1850
• Circulus delectabile (Tate, 1899)
• Circulus duplicatus (Lischke, 1872)
• Circulus gyalum (Melvill, 1904)
• Circulus harriettae (Petterd, 1884)
• Circulus liricincta (Garrett, 1873)
• Circulus modestum (Gould, 1859)
• 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)

The Database of Western Atlantic Marine Mollusca also adds the following species :

• Circulus orbignyi (P. Fischer, 1857) (dubious name)

Species brought into synonymy:

• Circulus carinulatus Locard, 1889 : synonym of Circulus striatus (Philippi, 1836)
• Circulus costulatus Locard, 1889 : synonym of Circulus striatus (Philippi, 1836)
• Circulus dalli Bush, 1897 : synonym of Cyclostremiscus dalli (Bush, 1897)
• Circulus tatei (Angas, 1878) : synonym of Elachorbis tatei (Angas, 1878)
• Circulus tricarinatus (Wood S., 1848) : synonym of accepted as Circulus striatus (Philippi, 1836)