Codonaria cistellula from the Bay of Villefranche in October 2014. Z-stack of images made using a 20x objective and DIC optics, lugol's-fixed specimen.
Drawing from Claparde & Lachmann 1858 (Plate 8, figure 5) of the species now known as Steenstrupiella steenstrupii as "Tintinnus steenstrupii". The scale bar reflects the text description (pg 200) as about 0.2 mm in overall length. The species (and now genus) was presumably named after the Danish biologist Japetus Steenstrup (1813-1897).