Pierre Belon was one of the first great explorer-naturalists, blazing a trail that would be followed by such luminaries as Damphier, Catesby, Humbolt, and Darwin. He is one of the foremost figures in the world of comparative anatomy, issuing some of the earliest works on homology. His Histoire Naturelle des Estranges Poissons Marins, published in 1551, is the first printed work devoted to fish (although it must be noted that Belon included such aquatic non-fish as the dolphin and hippopotamus). The work is notable for its beautiful woodcut illustrations and Belon’s accurate anatomical descriptions, many of which were based on his own dissections. His description and image of a cetacean fetus in utero is considered the first example of the science of embryology.