EntityQ17148674· pop 6· linked from 1,548 articlessutureSign in to savefairly rigid joint between two or more hard elements of an organismConnectionsVertebrataEntityMolluscaEntityGastropodaEntityAmmonoideaEntitycephalopod limbEntityLatinEntityanatomyEntityboneEntityInternational Standard Book NumberEntityskullEntitypearlEntityinvertebrateEntityWayback MachineEntityCrocodiliaEntityErnst HaeckelEntitylimestoneEntityjointEntityCambrianEntityCephalopodEntitychalkEntityCategoriesAnimal anatomyMollusc anatomySkeletal system