On the classification and geographical distribution of the Mammalia, being a lecture on Sir Robert Reade's foundation, delivered before the University of Cambridge ... May 10, 1859. To which is added an appendix "On the gorilla," and "On the extinction and transmutation of species." - Owen, Richard, 1804 -1892 (J. W. Parker and son, 1859)

On the contents of Gracilinanus Gardner and Creighton, 1989, with the description of a previously unrecognized clade of small didelphid marsupials - Lunde, Darrin P. (American Museum of Natural History, 2005)

On the domesticated animals of the British islands - Low, David. (Longman, Brown, Green & Longmans, 1845)

On the domesticated animals of the British islands : comprehending the natural and economical history of species and varieties; the description of the properties of external form; and observations on the principles and practice of breeding - Low, David, 1786 -1859 (Longman, Brown, Green & Longmans, 1845)

On the domesticated animals of the British islands: comprehending the natural and economical history of species and varieties; the description of the properties of external form; and observations on the principles and practice of breeding - Low, David, 1786 -1859 (Longman, Brown, Green, & Longmans, 1846)

On the form and structure of the Manatee (Manatus americanus) - Murie, James, 1832 -1925 (Zoological Society of London, 1872)

On the fossil mammals of Australia. parts 1-3, 6, 7 - Owen, Richard, 1804 -1892 (1859)

On the power, wisdom, and goodness of God : as manifested in the creation of animals, and in their history, habits, and instincts - Jones, Thomas Rymer, 1810 -1880 (H.G. Bohn, 1853)

On the primitive types of the orders of Mammalia Educabilia - Cope, E. D. (Edward Drinker), 1840 -1897 (1873)

On the relationships of "Marmosa" formosa Shamel, 1930 (Marsupialia, Didelphidae), a phylogenetic puzzle from the chaco of northern Argentina - Jansa, Sharon A. (American Museum of Natural History, 2004)

On the shoulder girdle of the mammalian subclass Allotheria - McKenna, Malcolm C. (American Museum of Natural History, 1961)

On the structure and development of the skull in the mammalia - Parker, William Kitchen William Kitchen Parker 1823 -1890 (Royal Society of London, 1874)

On the variation of species - Wollaston, Thomas Vernon, 1822 -1878 (John Van Voorst, 1856)

On the variation of species, with especial reference to the insecta followed by an inquiry into the nature of genera - Wollaston, Thomas Vernon, 1822 -1878 (J. Van Voorst, 1856)

On the variation of species : with especial reference to the Insecta : followed by an inquiry into the nature of genera - Wollaston, Thomas Vernon, 1822 -1878 (J. Van Voorst, 1856)

The ontogeny and phylogeny of the sternum - Hanson, Frank Blair, ([publisher not identified], 1919)

The orders of mammals - Gregory, William K. (William King), 1876 -1970 (The Trustees, 1910)

Organic evolution considered - Fairhurst, Alfred, 1843 -1921 (Christian publishing, 1897)

The organism as a whole : from a physicochemical viewpoint - Loeb, Jacques, 1859 -1924 (G. P. Putnam's sons, 1916)

The organism as a whole, from a physicochemical viewpoint - Loeb, Jacques, 1859 -1924 (Putnam's Sons, 1916)

The origin and affinities of the South American Condylarthra and early Tertiary Litopterna (Mammalia) - Cifelli, Richard (American Museum of Natural History, 1983)

The origin and evolution of life : on the theory of action, reaction and interaction of energy - Osborn, Henry Fairfield, 1857 -1935 (Scribner's, 1918)

The origin and evolution of life, on the theory of action, reaction and interaction of energy - Osborn, Henry Fairfield, 1857 -1935 (C. Scribner's Sons, 1917)

The origin of human reason, being an examination of recent hypotheses concerning it - Mivart, St. George Jackson, 1827 -1900 (K. Paul, Trench, 1889)

The origin of the fittest : essays on evolution - Cope, E. D. (Edward Drinker), 1840 -1897 (D. Appleton, 1887)

The origin of the fittest : essays on evolution - Cope, E. D. (Edward Drinker), 1840 -1897 (Macmillan and Company, 1887)

The origin of the fittest; essays on evolution - Cope, E. D. (Edward Drinker), 1840 -1897 (D. Appleton, 1887)

Ornithological bibliography - Coues, Elliott, 1842 -1899 (Geological Survey [etc.], 1878)

Ornithorhynchi paradoxi descriptio anatomica - Meckel, J. F. (Johann Friedrich), 1781 -1833 (1826)

The Osprey (The Osprey Co, 1900)

Die Osteologie und Myologie von Sciurus Vulgaris L., verglichen mit der Anatomie der Lemuriden und des Chiromys und ueber die Stellung des Letzteren im natürlichen Systeme - Hoffmann, C. K. 1841 -1903 (Loosjes Erben, 1870)

The osteology and myology of Didelphys virginiana - Coues, Elliott, 1842 -1899 (The Society, 1872)

Osteology of Andescynodon (Cynodontia, Traversodontidae) from the Middle Triassic of Argentina - Powell, Jaime Eduardo. (American Museum of Natural History, 2009)

Osteology of the Middle Eocene ceratomorph Hyrachyus modestus (Mammalia, Perissodactyla) - Wang, Yuanqing (Paleontologist) (American Museum of Natural History, 2017)

Osteology, phylogeny, and higher classification of the fishes of the order Plectognathi (Tetraodontiformes) - United States. National Marine Fisheries Service. (U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, 1980)

Othniel Charles Marsh - Beecher, Charles Emerson, 1856 -1904 (1899)

Othniel Charles Marsh - Beecher, Charles Emerson, 1856 -1904 (s.n, 1899)

Our country's animals and how to know them. A guide to the mammals, reptiles and amphibians of Great Britain - Gordon, W. J. (Simpkin, Marshall, Hamilton, Kent, 1904)

Our living world; an artistic edition of the Rev. J. G. Wood's Natural history of animate creation - Wood, J. G. (John George), 1827 -1889 (S. Hess, 1885)

An outline of the theory of organic evolution with a description of some of the phenomena which it explains - Metcalf, Maynard M. (Maynard Mayo), 1868 -1940 (MacMillan, 1906)

An outline of the theory of organic evolution, with a description of some of the phenomena which it explains - Metcalf, Maynard M. (Maynard Mayo), 1868 -1940 (The Macmillian company; [etc., etc.], 1906)

An outline of the theory of organic evolution, with a description of some of the phenomena which it explains - Metcalf, Maynard M. (Maynard Mayo), 1868 -1940 (The Macmillian company; [etc., etc.], 1904)

Outlines of chordate development - Kellicott, William E. (William Erskine), 1878 -1919 (Holt, 1913)

Outlines of chordate development - Kellicott, William E. (William Erskine), 1878 -1919 (H. Holt and company, 1913)

Outlines of comparative anatomy and medical zoology - Allen, Harrison, 1841 -1897 (Lippincott, 1874)

Outlines of comparative anatomy and medical zoology - Allen, Harrison, 1841 -1897 (J.B. Lippincott & co, 1869)

Outlines of comparative anatomy of vertebrates - Kingsley, J. S. (John Sterling), 1854 -1929 (P. Blakiston, 1917)

Outlines of comparative physiology : touching the structure and development of the races of animals, living and extinct - Agassiz, Louis, 1807 -1873 (H. G. Bohn, 1851)