The extremities, however, are still absent in these embryos. But even if they had existed in the earliest stage of their development we should learn nothing, for the feet of lizards and mammals, the wings and feet of birds, no less than the hands and feet of man, all arise from the same fundamental form."
Gorputzadarrik ez da ageri oraindik enbrioi hauetan, baina balituzte ere, lehen garapen-aldi honetan ez ligukete ezer erakutsiko, zeren saurio eta ugaztunen oinak, hegaztien hego eta oinak, eta era berean gizakiaren esku-oinak, guztiak baitatoz funtsezko forma berberarengandik".