Animals that live associated with the bottom of the ocean are referred to as benthic. Those that live associated with water away from the seafloor are referred to as pelagic. The crinoid echinoderms and their associates discussed here are benthic.
Many animals have both benthic and pelagic life stages–for instance, many benthic animals release their larvae into the water column. These pelagic larvae develop into juveniles and then settle back to the seafloor to live as benthic adults.