Solitary, generally applied to a single tooth in bivalves.
Spatulate, rounded and broad at the top, and becoming narrow like a spatula or battledore.
Species, the division of a family or genus, containing such as agree with it in general characters, or such as are derived from one common parentage.
Spiny, thorny, covered with thornlike processes.
Spinous, having spines like a hedgehog.
Spire, all the whorls of univalve shells, excepting the one in which the aperture is situated, which is termed the body.
Spiral, twisted like a corkscrew.
Squamose, scaly.
Stellated, starred, consisting of star-like figures.
Striated, scored, or covered with fine threadlike lines.