 The shells of these two last genera house a hypertrophied ctenidium large quantities of symbiotic bacteria.These snails are part of the fauna of the deep-sea hydrothermal vents, cold seeps, whale falls, and sunken driftwood environments.The family Provaniidae was previously placed in the "Zygopleuroid group" (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).