"After centuries of speculation, biologists have documented one way a strange group of octopuslike creatures use their seashell-shaped cases."
http://www.sciencenews.org/view/generic/id/59348/title/Argonauts_use_shells_as_flotation_devices
http://www.sciencenews.org/view/generic/id/59348/title/Argonauts_use_shells_as_flotation_devices