- sagittal
- salinity
- scalarid
- scarce
- schizogamy
- sculpture
- second lock
- sediment
- serrate
- sessile
- sex
- sexual dimorphism
- sheath
- shell
- shell growth
- Siboga
- side angle
- sinistral
- sinus
- siphon
- skeleton
- skinny stage
- SMFM
- somatic
- spatulate
- spec.
- species
- sperm
- sperma
- spermatophore
- spheroidal
- spine
- spine mark
- spine surface
- spine tip
- spinules
- spiral
- spire
- ssp.
- Stat.
- statocyst
- stenotherm
- Strait of Gibraltar
- striae
- striation
- styliform
- subadult
- subfossil
- subgenus
- subspecies
- subtropical submergence
- sucker
- sulcate
- sulcus
- sustentacular
- suture
- symbiosis
- sympatric
- synonym
- syntypes
- systematics