b ear ing ▁structures ▁that ▁they ▁interpreted ▁as ▁a ▁feed ing ▁appar atus ▁and ▁very ▁similar ▁to ▁that ▁of ▁W iw ax ia . ▁Od ont og ri ph us ’ s ▁feed ing ▁appar atus ▁was ▁located ▁on ▁the ▁mid line , ▁about ▁ 1 5 % ▁of ▁the ▁total ▁body ▁length ▁from ▁the ▁front ▁edge ▁of ▁the ▁foss ils . ▁The ▁mouth parts ▁compr ised ▁two ▁to ▁three ▁rows , ▁each ▁compr ising ▁about ▁two ▁dozen ▁carbon ace ous ▁teeth ▁arranged ▁symmet r ically ▁about ▁a ▁med ial ▁to oth , ▁with ▁one ▁or ▁two ▁later al ▁teeth ▁substantial ly ▁smaller ▁than ▁the ▁central ▁teeth . ▁The ▁teeth ▁operated ▁by ▁passing ▁around ▁an ▁underlying ▁" t ong ue ", ▁with ▁the ▁to oth ▁rows ▁de form ing ▁as ▁they ▁did ▁so . ▁The ▁teeth ▁probably ▁sc oop ed ▁through ▁the ▁sea - floor ▁mud , ▁feed ing ▁on ▁any ▁det rit us ▁within ▁it . ▁ ▁On ▁either ▁side ▁of ▁the ▁feed ing ▁appar atus ▁there ▁is ▁a ▁circular ▁structure ▁that ▁Car on , ▁Sch el tem a ▁et ▁al . ▁( 2 0 0 6 ) ▁interpreted ▁as ▁sal iv ary ▁g lands . ▁They ▁also ▁found ▁evidence ▁of ▁other ▁parts ▁of ▁the ▁dig est ive ▁tract : ▁a ▁g ul let ▁connecting ▁to ▁the ▁rear ▁of ▁the ▁mouth ; ▁a ▁relatively ▁short ▁st om ach ; ▁and ▁a ▁straight ▁much ▁longer ▁int est ine , ▁ending ▁at ▁an ▁an us ▁near ▁the ▁rear ▁of ▁the ▁unders ide . ▁A