So again, it is probable, from what we know of the embryos of mammals, birds, fishes and reptiles, that these animals are the modified descendants of some ancient progenitor, which was furnished in its adult state with branchiae, a swim-bladder, four fin-like limbs, and a long tail, all fitted for an aquatic life.
Daitekeena da halaber, ugaztun, hegazti, arrain eta narrastien enbrioiez dakigunetik, heldu-egoeran brankiak, igeri-maskuriak, hegats-formako lau gorputzadar eta buztan luze bat-uretan bizitzeko aproposak guztiok-zituen gurasolehenen baten ondorengo eraldatuak izatea animaliok.