C. apricarius is a shell-like structure filled with lighter-than-water substances. To keep it at an optimal water depth (temperature vs solar exposure), it has an anchor which it fills, or empties, with debris, depending on whether it needs to go up or down.
Living Relatives (click to show/hide)
None found. Note that this does not necessarily mean it has no living relatives at all, but that, assuming all taxonomy is filled in, its entire phylum is extinct; any relatives it does have likely do not resemble it.