On the Silurian Gastropoda and Pteropoda of Gotland - Lindström, Gustaf, 1829 -1901 (P.A. Norstedt, 1884)

On western Atlantic opisthobranchiate gastropods - Marcus, Ernst 1893 -1968 (American Museum of Natural History, 1958)

One hundred second annual report of the New York State Museum : Charles C. Adams, director - Adams, Charles C. (Charles Christopher), 1873 -1955 (University of the State of New York, 1940)

Ophiures de l'expédition du Siboga ... - Koehler, R. (René) 1860 -1931 (Librairie et imprimerie ci-devant E. J. Brill, 1904)

Opinions and declarations rendered by the International Commission on Zoological Nomenclature - International Commission on Zoological Nomenclature (Printed by order of the International Trust for Zoological Nomenclature, 1954)

Opisthobranch newsletter - Long, Steven J. (S.J. Long, 1969)

Opisthobranch newsletter - Long, Steven J. (S.J. Long, 1970)

Opisthobranch newsletter - Long, Steven J. (S.J. Long, 1977)

Opisthobranch newsletter - Long, Steven J. (S.J. Long, 1980)

Opisthobranch newsletter - Long, Steven J. (S.J. Long, 1981)

Opisthobranchian and lamellarian gastropods collected by the "Vema" - Marcus, Ernst 1893 -1968 (American Museum of Natural History, 1969)

Ostracoda - Müller, Gustav Wilhelm, 1857 - (Gustav Fischer, 1905)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1888)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1889)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1896)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1895)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1899)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1900)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1903)

Our country's shells and how to know them : a guide to the British mollusca - Gordon, W. J. (Simpkin, Marshall, Hamilton, Kent & Co, 1901)

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 natural history of our shores - Sinel, Joseph. (S. Sonnenschein, 1906)

An outline of the natural history of our shores - Sinel, Joseph. (Swan Sonnenschein & Co, 1906)

Outlines of comparative anatomy - Grant, Robert Edmond, 1793 -1874 (Bailliere, 1841)

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)