( ( In ( eutherian ( -LRB- ( placental ( -RRB- mammals ) ) ) ) ) ( , ( ( the hemispheres ) ( ( are ( linked ( by ( ( ( the ( corpus callosum ) ) , ) ( ( a ( ( very large ) bundle ) ) ( of ( nerve fibers ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN In) (NP (JJ eutherian) (-LRB- -LRB-) (NN placental) (-RRB- -RRB-) (NNS mammals))) (, ,) (NP (DT the) (NNS hemispheres)) (VP (VBP are) (VP (VBN linked) (PP (IN by) (NP (NP (DT the) (NN corpus) (NN callosum)) (, ,) (NP (NP (DT a) (ADJP (RB very) (JJ large)) (NN bundle)) (PP (IN of) (NP (NN nerve) (NNS fibers)))))))) (. .)))
In eutherian (placental) mammals, the hemispheres are linked by the corpus callosum, a very large bundle of nerve fibers.
(ROOT (S (NP (JJ Placental) (NNS mammals)) (VP (VBP give) (NP (NN birth)) (PP (TO to) (NP (ADJP (RB relatively) (JJ large)) (NNS fetuses)))) (. .)))