Spiral Tubeworms

Spirorbis is a genus of very small (2–5 mm (0.079–0.197 in)) 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 Daudin, 1800 Spirorbis corallinae De Silva and Knight-jones, 1962 Spirorbis cuneatus Gee, 1964 Spirorbis granulatus Spirorbis incongruus Spirorbis inornatus L'hardy and Quievreux, 1962 Spirorbis knightjonesi Desilva, 1965 Spirorbis lineatus Spirorbis marioni (Caullery and Mesnil, 1897) Spirorbis medius Spirorbis moerchi Spirorbis nakamurai Spirorbis quadrangularis Spirorbis quasimilitaris Bailey, 1970 Spirorbis rupestris Gee and Knight-jones, 1962 Spirorbis semidentatus Spirorbis similis Spirorbis spirorbis (Linnaeus, 1758) Spirorbis steueri Sterzinger, 1909 Spirorbis tridentata Levinsen, 1883 Spirorbis variabilis Spirorbis violaceus

Here is the original description of Daudin (1800): "GENRE SPIRORBE. SPIRORBIS. Caractère generIque. Coquille discoïde, régulière , à ouverture sub-orbiculaire, et toujours adhérente aux substances marines. Ce genre, quoique voisin des Planorbes par la forme de sa coquille plus comprimée dans le centre, appartient cependant à la sous-division des vers à tuyaux, au moins l'espèce nommée par Linné serpula spirorbis , parce qu'elle renferme une véritable amphytrite à quatre plumules attachées contre la base d'un tentacule bifide , suivant le citoyen Bosc. Les trois espèces suivantes , deja connues , sont toujours fixées après les coraux , les coquilles , les fucus , les algues et autres substances marines." [Translation: "SPIRORBE GENUS. Spirorbis. Generic character. Discoid shell, regular, with sub-orbicular opening, and always adherent to marine substances. This genus, though close to the Planorbes by the shape of its more compressed shell in the center, belongs, however, to the sub-division of pipe-worms, at least the species named by Linnea Serpula spirorbis, because it contains a true amphytrite. four plumules tied against the base of a bifid tentacle, according to the citizen Bosc. The following three species, already known, are always fixed after [on] corals, shells, fucus, algae and other marine substances."