Spirorbis is a genus of very small (2-5mm) polychaete worms, usually with a white coiled shell. Members of the genus live in the lower littoral and sublittoral zones of rocky shores. Spirorbis worms usually live attached to seaweeds, but some species live directly on rocks, shells or other hard substrates. Spirorbis was once thought to have a fossil record extending back into the Early Paleozoic, but now all pre-Cretaceous spirorbins are known to be microconchids. The earliest members of genus appeared in the Miocene, but Oligocene finds may also be possible. The genus contains the following species:
- Spirorbis borealis
- Spirorbis corallinae
- Spirorbis cuneatus
- Spirorbis granulatus
- Spirorbis incongruus
- Spirorbis inornatus
- Spirorbis knightjonesi
- Spirorbis lineatus
- Spirorbis marioni
- Spirorbis medius
- Spirorbis moerchi
- Spirorbis nakamurai
- Spirorbis quadrangularis
- Spirorbis quasimilitaris
- Spirorbis rupestris
- Spirorbis semidentatus
- Spirorbis similis
- Spirorbis spirorbis
- Spirorbis steueri
- Spirorbis tridentata
- Spirorbis variabilis
- Spirorbis violaceus