to descend, not from the "bird-hipped" Ornithischia, but from the "lizard-hipped" Saurischia. He found the two groups so distinct that he also argued for separate origins: not until the 1980s did new techniques of cladistic analysis show that both groups of dinosaurs really did have common ancestors in the Triassic. Seeley described and named numerous dinosaurs from their fossils in the course of his career. His popular book on pterosaurs, Dragons of the Air (1901), found that the development of birds and pterosaurs paralleled each other. His belief that they had a common origin has been proved, for both are archosaurs, just not as close as he thought. He upset Richard Owen's characterization of the pterosaurs as cold-blooded, sluggish gliders, and recognized them as warm-blooded active fliers. He was elected a Fellow of the Royal Society in June 1879 for his work on reptiles and dinosaurs, and delivered their Croonian Lecture in 1887. - see Alfred Brown Publications The Ornithosauria (1870) Factors in Life: Three Lectures on Health, Food, Education (1884) Manual of Geology: Theoretical and Practical (1885) The Freshwater Fishes Of Europe: A History Of Their Genera, Species, Structure, Habits And Distribution (1886) The Story of the Earth in Past Ages (1895) Dragons of the air : an account of extinct flying reptiles (1901) References Further reading External links Dragons of the Air (1901) at HathiTrust Michon Scott, "Harry Govier Seeley" Harry G. Seeley British palaeontologists 1839 births 1909 deaths Academics of King's College London Fellows of the Royal Society Lyell Medal winners Scientists from London Burials at Brookwood Cemetery