Function of Shell Sculpture in Marine Gastropods: Hydrodynamic Destabilization in Ceratostoma foliatum.

The gastropod Ceratostoma foliatum (Gmelin) possesses three bladelike varices on the body whorl of the shell. The precise positioning and relative width of these varices destabilize the animal as it falls through the water, substantially increasing the chances that it will land upright (aperture down). For a gastropod pulled off rocks and dropped by predatory fish, such a mechanism could considerably reduce its probability of being eaten.