 The <unk> is a distinctive bones found lining the frills of ceratopsians . The name is a <unk> , as they are not associated with the <unk> bone . <unk> begin as separate bones that fuse during the animal 's growth to either the <unk> or parietal bones that make up the base of the frill . These bones were ornamental instead of functional , and may have helped differentiate species . <unk> probably were present in all known ceratopsids with the possible exception of Zuniceratops . They appear to have been broadly different between short @-@ frilled ceratopsids ( <unk> ) and long @-@ frilled ceratopsids ( <unk> ) , being elliptical with <unk> bases in the former group , and triangular with wide bases in the latter group . Within these broad definitions , different species would have somewhat different shapes and numbers . In <unk> especially , like Centrosaurus , <unk> , and <unk> , these bones become long and <unk> or hook @-@ like . A well @-@ known example is the coarse <unk> fringe of broad triangular <unk> on the frill of Triceratops . When regarding the ossification 's <unk> traits , it can be described as dermal . The term <unk> was coined by famous paleontologist Othniel Charles Marsh in 1889 . 
