el id ▁w orm s ▁and ▁bra chi op ods . ▁Car on , ▁Sch el tem a ▁et ▁al . ▁( 2 0 0 6 ) ▁interpreted ▁Od ont og ri ph us ’ s ▁feed ing ▁appar atus ▁as ▁a ▁for er un ner ▁of ▁the ▁m oll us can ▁rad ula , ▁on ▁the ▁grounds ▁that : ▁the ▁occas ional ▁and ▁less ▁distinct ▁third ▁to oth - row ▁looked ▁like ▁evidence ▁that ▁the ▁animals ▁grew ▁replacement ▁to oth - rows ▁at ▁the ▁rear ▁of ▁their ▁mouth s ▁and ▁shed ▁worn - out ▁ones ▁from ▁the ▁front , ▁as ▁happens ▁with ▁m oll us can ▁rad ula e ; ▁the ▁isolated ▁pairs ▁of ▁to oth - rows ▁they ▁found , ▁not ▁associated ▁with ▁body ▁foss ils ▁but ▁in ▁the ▁same ▁relative ▁positions ▁as ▁in ▁the ▁more ▁complete ▁foss ils , ▁suggested ▁they ▁were ▁mounted ▁on ▁fairly ▁t ough ▁surfaces , ▁like ▁the ▁ch it in ous ▁" bel ts " ▁of ▁modern ▁rad ula e ; ▁they ▁even ▁found ▁signs ▁that ▁disc arded ▁to oth - rows ▁were ▁sometimes ▁e aten ▁by ▁the ▁animals . ▁Hence ▁they ▁class ified ▁both ▁Od ont og ri ph us , ▁and ▁W iw ax ia ▁with ▁its ▁" near ly ▁identical " ▁feed ing ▁appar atus , ▁as ▁primitive ▁relatives ▁of ▁m oll us cs . ▁ ▁In ▁line ▁with ▁this ▁classification ▁they ▁interpreted ▁the ▁dark ▁patch es ▁round ▁the ▁foot ▁as ▁g ill - like ▁c ten idia , ▁another ▁feature ▁of ▁some