1 8 7 4 ; ▁ 2 nd ▁edition , ▁ 1 8 7 8 ), ▁translated ▁into ▁English ▁by ▁Francis ▁Jeff rey ▁Bell ▁( as ▁Element s ▁of ▁Compar ative ▁An atom y , ▁ 1 8 7 8 ), ▁with ▁add itions ▁by ▁E . ▁Ray ▁L ank ester . ▁While ▁recogn izing ▁the ▁importance ▁of ▁compar ative ▁emb ry ology ▁in ▁the ▁study ▁of ▁descent , ▁Gegen ba ur ▁laid ▁stress ▁on ▁the ▁higher ▁value ▁of ▁compar ative ▁an atom y ▁as ▁the ▁basis ▁of ▁the ▁study ▁of ▁hom ologies , ▁i . e . ▁of ▁the ▁relations ▁between ▁corresponding ▁parts ▁in ▁different ▁animals , ▁as , ▁for ▁example , ▁the ▁arm ▁of ▁man , ▁with ▁the ▁fore leg ▁of ▁a ▁horse , ▁and ▁with ▁the ▁wing ▁of ▁a ▁f ow l . ▁A ▁distinct ive ▁piece ▁of ▁work ▁was ▁effect ed ▁by ▁him ▁in ▁ 1 8 7 1 ▁in ▁supp lement ing ▁the ▁evidence ▁ad du ced ▁by ▁H ux ley ▁in ▁ref ut ation ▁of ▁the ▁sk ull - verte bra e ▁theory : ▁the ▁theory ▁of ▁the ▁origin ▁of ▁the ▁sk ull ▁from ▁expanded ▁verte bra e , ▁which , ▁form ulated ▁independently ▁by ▁Go ethe ▁and ▁O ken , ▁had ▁been ▁champion ed ▁by ▁O wen . ▁H ux ley ▁demonstrated ▁that ▁the ▁sk ull ▁is ▁built ▁up ▁of ▁cart il agin ous ▁pieces ; ▁Gegen ba ur ▁showed ▁that ▁in ▁the ▁lowest ▁( gr ist ly ) ▁fish es , ▁where ▁hints ▁of ▁the