Opisthosiphon is a genus of land snails with an operculum, terrestrial gastropod mollusks in the family Annulariidae.

The genus Opisthosiphon has been described by American malacologist William Healey Dall in 1905.

Type: Chondropoma Bahamense, Sh.

Shell with the habit of Chondropoma dentatum, Say, but in the adult with a tubular projection behind and distinct from the outer lip and the posterior angle of the aperture, but communicating with the

operculum as in Rhytidopoma, but thinner.The following species are recognised in the genus Opisthosiphon:[2] This article incorporates public domain text from the reference[1]