Swimming \textit{Vorticella convallaria} in various confined geometries

\textit{Vorticella convallaria} is a stalked ciliate observed in the sessile form (trophont) or swimming form (telotroch). Trophonts are mainly composed of an inverted bell-shaped cell body generating vortical feeding currents, and a slender stalk attaching the cell body to a substrate. If the surrounding environment is no longer suitable, the trophont transforms into a telotroch by elongating its cell body into a cylindrical shape, resorbing its oral cilia and producing an aboral cilia wreath. After a series of contractions, the telotroch will completely detach from the stalk and swim away to find a better location. While sessile \textit{Vorticella} has been widely studied because of its stalk contraction and usefulness in waste treatment, \textit{Vorticella}'s swimming has not yet been characterized. The purpose of this study is to describe \textit{V. convallaria}'s swimming modes, both in its trophont and telotroch forms, in different confined geometries. Using video microscopy, we observed \textit{Vorticellae} swimming in semi-infinite field, in Hele-Shaw configurations, and in capillary tubes. Based on measured swimming displacement and velocity, we investigated how \textit{V. convallaria}'s mobility was affected by the geometry constrictions.