Haeckel on animal and human embryos, 1874 illustrations. The embryos are shown in two stages of development, from top to bottom. They are (from left to right): a tortoise, a chicken, a dog, and a human. This page is from a work on embryology by German naturalist Ernst Haeckel (1834-1919). Haeckel's pictures were meant to show the initial similarity of the embryos, and argue this as evidence that humans share a common ancestry with these animals (the biogenetic law). Haeckel's pictures appeared in many textbooks until proved fraudulent by later scientists. This page is from an 1874 edition of Haekel's work 'Naturliche Schopfungsgeschichte' (The History of Creation), first published in 1868.