The Systematic Position of the Family Caecidae (Mollusca: Gastropoda)

The Family Caecidae has been placed near the Vermetidae in the superfamily Cerithiacea since Clark published his views in 1855. Close examination of the animals shows the caecids to have a close relationship to the superfamily Rissoacea. Animals of the Vitrinellidae were most similar to the Caecidae, and the shells of the Ctiloceratidae showed affinity to both the Caecidae and the Vitrinellidae. No close relationship between the Caecidae and Vermetidae or other Cerithiacea could be demonstrated, and both the Caecidae and Ctiloceratidae are transferred from the Cerithiacea to the Rissoacea.