▁were ▁buried ▁and ▁foss il ized , ▁and ▁smaller ▁or ▁internal ▁features ▁appear ▁as ▁mark ings ▁within ▁the ▁out lines ▁of ▁the ▁foss ils . ▁ ▁Wh itt ington ▁interpreted ▁as ▁g ills ▁some ▁mark ings ▁on ▁the ▁upper ▁surfaces ▁of ▁all ▁lo bes ▁except ▁the ▁first ▁on ▁each ▁side , ▁and ▁thought ▁that ▁these ▁g ills ▁were ▁flat ▁under ne ath , ▁had ▁over la pping ▁layers ▁on ▁top , ▁and ▁attached ▁to ▁the ▁bases ▁of ▁the ▁lo bes . ▁Bud d ▁( 1 9 9 6 , ▁ 2 0 1 1 ) ▁thought ▁they ▁consisted ▁of ▁separate ▁" bl ades " ▁attached ▁along ▁the ▁front ▁edges ▁on ▁the ▁unders ides ▁of ▁the ▁lo bes . ▁He ▁also ▁found ▁marks ▁inside ▁the ▁lo bes ' ▁front ▁edges ▁that ▁he ▁interpreted ▁as ▁internal ▁channels ▁connecting ▁the ▁g ills ▁to ▁the ▁interior ▁of ▁the ▁body , ▁much ▁as ▁Wh itt ington ▁interpreted ▁the ▁mark ▁along ▁the ▁prob os cis ▁as ▁an ▁internal ▁channel . ▁On ▁the ▁other ▁hand , ▁Berg ström ▁( 1 9 8 6 ) ▁interpreted ▁both ▁the ▁" g ills " ▁and ▁the ▁lo bes ▁as ▁part ▁of ▁a ▁covering ▁over ▁the ▁upper ▁surface ▁of ▁the ▁body . ▁ ▁Wh itt ington ▁found ▁evidence ▁of ▁near - tri angular ▁features ▁along ▁the ▁body , ▁and ▁concluded ▁that ▁they ▁were ▁internal ▁structures , ▁most ▁likely ▁side ways ▁extensions ▁of ▁the ▁gut . ▁Chen ▁et ▁al . ▁( 1 9 9 4 ) ▁interpreted ▁them ▁as ▁contained ▁within ▁the ▁lo bes ▁along