In the late 1800, a German naturalist named Ernst Haeckle produce a series of drawings showing animal embryos. Through his drawings it was obvious that early embryos shared many things in common although they belonged to different animals like fish, humans, turtles, salamanders... There seemed to be remarkable similarities among those early animal embryos. Charles Darwin based his theory of comment descent on evidence like this great biology discovery, only to be proved later as a great biology hoax!
Haeckel faked these drawings. Embryos of different animals have little or no similarities between them. Worst is that even today, one can find biology books with referrals to Haeckels' drawings!
The drawings entered the books (and even in College text books) decades later and never have been taken out. Many times the drawings do not even refer as Haeckel's drawings.