( Pycnogonids ( ( are ( one ( of ( ( the ( few groups ) ) ( of ( animals ( ( in which ) ( ( ( ( ( the males ) ( ( exclusive - ) ( ( ly brood ) ( the ( developing embryos ) ) ) ) ) and ) , ) ( in ( ( ( some species ) , ) ( the young ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Pycnogonids)) (VP (VBP are) (NP (NP (CD one)) (PP (IN of) (NP (NP (DT the) (JJ few) (NNS groups)) (PP (IN of) (NP (NP (NNS animals)) (SBAR (WHPP (IN in) (WHNP (WDT which))) (S (S (NP (DT the) (NNS males)) (VP (VBZ exclusive) (: -) (S (NP (NN ly) (NN brood)) (NP (DT the) (VBG developing) (NNS embryos))))) (CC and) (, ,) (PP (IN in) (NP (NP (DT some) (NN species)) (, ,) (NP (DT the) (JJ young)))))))))))) (. .)))
Pycnogonids are one of the few groups of animals in which the males exclusive- ly brood the developing embryos and, in some species, the young.
(ROOT (S (NP (NP (NNS Invertebrates)) (-LRB- -LRB-) (CC and) (NP (JJR higher) (NNS animals)) (-RRB- -RRB-)) (VP (MD can) (ADVP (RB also)) (VP (VB be) (VP (VBN placed) (PP (IN in) (NP (NP (CD one)) (PP (IN of) (NP (CD two) (NNS groups))))) (PP (VBN based) (PP (IN on) (SBAR (WHADVP (WRB how)) (S (NP (PRP they)) (VP (VBP develop) (PP (IN as) (NP (NNS embryos))))))))))) (. .)))
Invertebrates (and higher animals) can also be placed in one of two groups based on how they develop as embryos.