( ( ( pronograde progression ) ( on ( all ( four limbs ) ) ) ) . )
(ROOT (S (VP (VB pronograde) (NP (NN progression)) (PP (IN on) (NP (DT all) (CD four) (NNS limbs)))) (. .)))
pronograde progression on all four limbs.
(ROOT (S (NP (DT All) (NNS mammals)) (VP (VBP have) (NP (CD four) (NNS limbs))) (. .)))