( Then ( however ( ( the ( immune system ) ) ( ( was ( ( discovered , ) ( which ( is ( of ( ( the ( same kind ) ) ( in ( ( these respects ) ( as ( the ( circulatory system ) ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (RB Then) (ADVP (RB however)) (NP (DT the) (JJ immune) (NN system)) (VP (VBD was) (VP (VBN discovered) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (PP (IN of) (NP (NP (DT the) (JJ same) (NN kind)) (PP (IN in) (NP (NP (DT these) (NNS respects)) (PP (IN as) (NP (DT the) (JJ circulatory) (NN system)))))))))))) (. .)))
Then however the immune system was discovered, which is of the same kind in these respects as the circulatory system.
(ROOT (S (NP (NNS Echinoderms)) (VP (VBP possess) (NP (DT a) (JJ water-based) (NN circulatory) (NN system))) (. .)))