[1] EDWARD F. O'BRIEN (Leadenhall Street, London). Letter (1865) [2-5] M.R. O'MALY. Letters (1868) [6-8] JAMES DOUGLAS OGILBY (1853-1925) (ichthyologist, taxonomist). Letters (1876-81) [9-10] FERGUS MENTEITH OGILVIE (1862-1918) (ophthalmic surgeon). Letters (1888-91) [11] THOMAS OLDHAM (1816-78) (Professor of Geology, Trinity College Dublin, 1845-50; Superintendant, Geological Survey of India, 1850-76). Letter (1874) [12] OLE THEODOR OLSEN (1838-1925) (writer, publisher; secretary, Marine Fisheries Society, Grimsby). Letter (1889) [21-56] SIR JOHN WILLIAM POWLETT ORDE (later CAMPBELL-ORDE) (1827-97) (3rd Baronet). Letters (1859-85) [13-16] JOHN ORFEUR (Norfolk and Norwich Naturalists' Society). Letters (1879) [17-18] ELEANOR ANNE ORMEROD (1828-1901) (economic entomologist). Letter (1886) [19] HENRY OSBURN. Letter (1866) [20] E.L.D. OWEN (son of Rector of Bradwell, Essex). Letter (1874) [57-85] SIR RICHARD OWEN (1804-92) (Hunterian Professor of Comparative Anatomy and Physiology, Royal College of Surgeons, 1836-56; Superintendent of Natural History Collections, British Museum, 1856-83). Letters (1856-72)