| Simplaria P. Knight-Jones, 1984 |
| Simplaria pseudomilitaris (Thiriot-Quiévreux, 1965) |
| Simplaria regalis (Bailey & M.P. Harris, 1968) |
| Sphaeropomatus Treadwell, 1934 |
| Sphaeropomatus miamiensis Treadwell, 1934 |
| Spiraserpula Regenhardt, 1961 |
| Spiraserpula caribensis Pillai & ten Hove, 1994 |
| Spiraserpula karpatensis Pillai & ten Hove, 1994 |
| Spiraserpula nudicristata Pillai & ten Hove, 1994 |
| Spiraserpula paraypsilon Pillai & ten Hove, 1994 |
| Spiraserpula plaiae Pillai & ten Hove, 1994 |
| Spiraserpula singularis Pillai & ten Hove, 1994 |
| Spiraserpula ypsilon Pillai & ten Hove, 1994 |
| Spiraserpula zibrowii Pillai & ten Hove, 1994 |
| Spirobranchus de Blainville, 1818 |
| Spirobranchus americanus (Day, 1973) |
| Spirobranchus augeneri ten Hove, 1970 |
| Spirobranchus dendropoma Mörch, 1863 |
| Spirobranchus gaymardi (de Quatrefages, 1866) |
| Spirobranchus giganteus (Pallas, 1766) |