Their locomotion was relative to the water mass in which they lived but the exact mechanisms (such as turbulence, buoyancy, active swimming, and so forth) are not clear yet. The most likely option was rowing or swimming by undulatory motion with muscular appendages or with the feeding tentacles. However, in some species, the thecal aperture was probably so restricted that the appendages hypothesis is not feasible. On the other hand, buoyancy is not supported by any extra thecal tissue or gas build-up control mechanism, and active swimming requires a lot of energetic waste, which would rather be used for the tubarium construction.