Haeckel on animal and human embryos, 1903 illustration. The embryos are shown developing in three stages, from top to bottom. From left to right, the embryos shown here are: marsupial, pig, deer, cattle, dog, bat, rabbit and 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 a 1903 edition of Haekel's work on embryology and evolution 'Anthropogenie oder Entwickelungsgeschichte des Menschen' (Anthropogeny: Or, the Evolutionary History of Man), first published in 1874.