Toxodon platensis fossil teeth together with the illustrations featured in George Sharf's life-sized lithograph (pl. IV) from 'The Zoology of the Voyage of HMS Beagle' under the supervision of Charles Darwin, Part 1, 'Fossil Mammalia' by Richard Owen (1838). Toxodon was one of the many striking extinct giant mammals that Darwin discovered while travelling overland in South America during the Voyage of the Beagle. Toxodon was named by Richard Owen (at that time a friend, but later a bitter enemy) after the curvature evident in the profile of the teeth. Toxodon means 'bow tooth'. Though Toxodon has no living relatives, many of the other fossils Darwin found were related to the animals still living there. Darwin wondered if they were ancestors, and in later years would cite these fossils (and also Galapagos) as 'the origin of all my views'.